NFL play-off prep

It's Sunday, it's the NFL play-offs, it's only a matter time before controversy ensues. Why not brush up on the NFL Digest of Rules so you know who's right. While you're there, you might as well learn those crazy NFL Official Signals too. That's not Traveling, buddy, that's "False Start, Illegal Formation, Kickoff or Safety Kick Out of Bounds." (And what's Illegal Crackback? Is that when I lean over while wearing my low-rise jeans?)