In a game against the Chicago Bears last month, Eric Bassey of the St. Louis Rams went out for a pass on a fake punt and was tackled before the ball arrived. He sprang to his feet, confident he had drawn a penalty. A clear case of pass interference.

"He hits me well before the ball gets there," Bassey said. "I'm thinking it's got to be something, so of course when I get up, I'm throwing my hands up saying, 'Throw the flag!"'

Sorry, Eric. Apparently you weren't familiar with Note No. 5 under Article 5 under Section 2 under Rule 8 on page 54 of the NFL rule book. There it is, plain as day: "Whenever a team presents an apparent punting formation, defensive pass interference is not to be called for action on the end man on the line of scrimmage."

In plainer English, that means the two guys who line up wide on either side in punt formation — the gunners, as they are known in the locker room — can never be victims of pass interference. They can be leveled with impunity anytime a defender sees the ball coming their way.

Didn't know that? Don't worry. A lot of players didn't, either, until Bassey found out the hard way.

"Something's going to have to come up for you to learn that one," Bassey said.

That one, plus many others. For, as recent games have shown, the NFL has yet to meet a rule it doesn't like — or like to have variations of.

Take the fair catch. Can you signal with two hands, or does it always have to be one?

Or let's say a receiver makes a nice play to get his toes inbounds as he's catching a pass — is it still a catch if his heels then come down on the sideline?

Or how about that infamous 11-10 game between Pittsburgh and San Diego last month, when the league had to issue a head-spinning, 450-word press release to explain why the officials messed up by not allowing a Steelers touchdown on the final play?

"There's so many obscure rules," said Washington Redskins long snapper Ethan Albright, a 14-year veteran. "I don't know how the referees know them, and they do it for a living."

The rule book has become so thick — the online version runs 112 pages — that the players, coaches and even the officials aren't always sure what the call should be. It's reached the point that the league's vice president of officiating, Mike Pereira, has begun sending out regular tapes parsing the most subtle nuances of calls made in recent games, with commentary lines such as: "This is not a field goal attempt because it is kicking a backward pass." He also contributes a weekly "Official Review" segment on the NFL Network.

It all begs the question: Has the game become too complicated for its own good?

"Let me just say I don't read James Michener at night when I go home," Pereira said. "My reading has always been the rule book. Even though I've been at it for so long, I literally have to keep reading it all the time so that I can try to stay up to date on everything. But every once in a while there are still a couple of plays that crop up where you go, 'Wait a minute. What is the rule on that?' And then I have to get back into the book and find it."

The enthusiasm in Pereira's voice is unmistakable. He sounds like a physics student poring over Einstein's relativity papers.

"It's insane," he said, "but to me it's really kind of fun to read the rule book — because I learn all the time when I read it."

Of course, most people have never fully grasped Einstein, and the same could be said for the NFL's tome of regulations. Even former Redskins coach Joe Gibbs, who has a bust in the Hall of Fame, was embarrassed last year to learn that his back-to-back timeouts to freeze a kicker constituted grounds for an automatic 15-yard unsportsmanlike conduct penalty.

"You really do have to familiarize yourself with all the rules so you know what's going on at all times," Baltimore Ravens cornerback Fabian Washington said. "It's kind of confusing sometimes. The main thing is hopefully somebody knows what's going on."

Usually the officials make the correct call, although it might require a conference or use of replay — resulting in tedious delays that irritate both fans and players.

"It kind of breaks the continuity of the game," Pittsburgh Steelers safety Ryan Clark said.

There's even an occasion or two when an official needs advice from the sidelines. "There's been situations over the years where I've helped them at times," said Tennessee Titans coach Jeff Fisher, who knows the rules particularly well as co-chair of the league's competition committee.

That's all fine once the play is over, but what about during the play, when everything is full speed? Albright points out a recent rule change that says anyone covering a punt can push an opponent in the back — but only after the ball is caught.

"So the referee's got to look — 'All right, he pushed them in the back. Did the punt return guy have the ball? Or was the ball still in the air? If the ball was still in the air, it's a penalty.' Stuff like this is just mind-boggling," Albright said.

It's not surprising that the strangest rules involve special teams. The rule voiding the pass interference against Bassey came about because the gunner is usually tussling with his defender from the moment the ball is snapped. So the NFL didn't want punters just sending the ball in that direction to pick up an easy penalty.

The fair catch signal, as Washington's Ryan Boschetti to his chagrin learned this year, cannot be made with two hands. (He was flagged 5 yards for his ignorance.) Nor can a player call for a fair catch after the ball hits the ground, as Dallas Cowboys returner Patrick Crayton tried to do against Chicago this year. (Another 5-yard penalty.)

Even Fisher needed some clarification from the officials during a loss to the New York Jets last month. Titans receiver Justin Gage made a great catch on the sideline with tiptoes of both feet clearly inbounds, but the pass was ruled incomplete. After Fisher threw the red flag to challenge the play, officials came over and told the coach that Gage's heels subsequently came down on the white line. No catch.

"It was something that we hadn't seen in years," Fisher said.

A new trend in recent years is the out-of-bounds kickoff ploy. In a game against Buffalo, New York Jets kick returner Leon Washington deliberately stepped out of bounds before touching a kickoff that was still inbounds. Under the rules, that's a penalty for an out-of-bounds kickoff, so the Jets got the ball at the 40 instead of the 8 — and took advantage of the good field position to score a touchdown.

"That's been one of my favorites," Pereira said, "because every special teams coordinator teaches it."

Sometimes, however, the correct interpretation doesn't make it all the way to the player. Minnesota's Adrian Peterson goofed up the maneuver in a big way when he touched a kickoff and then stepped out of bounds — at his 1-yard line. The Vikings had to start the drive right there.

The ending to the Steelers-Chargers 11-10 game defies a simple explanation, but suffice it to say the NFL had to cite three different rules regarding legal and illegal forward and backward passes to explain why Troy Polamalu's touchdown should have counted. Fortunately, the Steelers won the game anyway, so the only people smarting were the gamblers betting on the spread.

Perhaps the most bizarre rule involves a novel way to convert the extra point after a touchdown. Let's say the holder bobbles the snap and the ball is rolling around, and then a defensive player intentionally kicks or knocks it out of his own end zone.

In that case, the kicking team is awarded the extra point — without even possessing the ball. And if that team was attempting a 2-point conversion and the same thing happened, it would get one point.

"The ball actually gets knocked out of bounds, and you get a point," said Redskins special teams coordinator Danny Smith, who has that rule specially marked in a book in his office. "Figure that out."

Officials keep abreast on all rules obvious and obscure by taking three league-required tests totaling 400 questions during the preseason, plus weekly tests with about 50 questions during the season. In every game crew, Pereira said, there is usually one official known as "the master rule guy."

"We understand errors of judgment, but we're not very tolerant of misenforcement of rules," Pereira said. "And really when you look at it, I would say 98 percent of what happens in a weekend is routine, and then maybe 2 percent is something that's a little abnormal."

Those wishing for a thinner rule book have a major tidal wave going against them: football, even in its basic form, is a very complicated game.

Soccer? Kick the ball in the goal and don't use your hands. Football has first downs, legal and illegal forward passes, ineligible receivers, punts, holding, pass interference, drop kicks, free kicks, play clocks, two-minute warnings — enough to require seven officials on the field to keep track of it all, plus another in the replay booth.

Pereira points out that every new rule has a rationale, whether it's to improve player safety or to address a situation that's come up in a recent game, or essentially to make sure that every possible scenario is covered.

"You have to go back and look at the history of this game," Pereira said. "This game's been around for so long, and each year there are issues that are brought up by clubs and by players and by the league which are appropriate changes. And when you have this many years gone by it tends to get complicated, but I think it's necessarily complicated."

And some, it must be said, find the maze of rules fascinating. There are always coaches and players looking through the pages, trying to find some quirk they can use to their advantage.

Either way, it helps to be well-versed.

"We go over a lot of different things, a lot of different scenarios, and things that could happen and things that have happened in the past," Buffalo Bills punter Brian Moorman said. "You look at tape. You do everything you can to learn them all, but at the end of the day, sometimes you're just going to learn a new one on Sunday."

Associated Press Sports Writers R.B. Fallstrom in St. Louis; David Ginsburg in Owings Mills, Md.; Pat Graham in Englewood, Colo.; Andrew Bagnato in Tempe, Ariz.; John Wawrow in Buffalo, N.Y.; Larry Lage in Allen Park, Mich.; Mark Long in Jacksonville, Fla.; Alan Robinson in Pittsburgh; and Teresa M. Walker in Nashville, Tenn., contributed to this report.