Go to the Apocalypto trailer. Play until you see the screaming monkey (about 70% or so through,) backtrack a frame at a time until the first monkey frame, then backtrack 6 more frames. Surprise!
(from a friend’s blog)
Boy, I hope this isn’t already common knowledge.
Would it be possible for somebody to post what it is in a spoiler box?
Mel Gibson leaning on some heavily made-up extra’s shoulder, smoking a cigarette, with a goofy, shit-eating grin on his face. 
I’m guessing it’s Mel with a crazy beard and crazier grin since a frame capture of that made the media rounds ages ago.
Please feel free to correct me if I’m wrong.
Yep, but it’s funnier if you dredge the trailer for it.
Just out of curiosity, what the hell kind of software gives you the capability to backtrack through a vid one frame at a time?
This is one of the funniest things I’ve seen in a while.
I lost a lot of respect for Gibson after what he’s done lately, but I have to say it’s hard for me to completely hate someone with the humor to hide something like that in such a serious, intense trailer.
I can do that with the remote of my Toshiba TV/DVD combo. Hardly state of the art!
Just click on the pause button of the Quicktime player and use your arrow keys.