The second time that Ben Stiller snaps his fingers during the movie (34 minutes in), press ENTER and you will be taken to a major unadvertised extra: writer-director Rawson Thurber's solo audio commentary (without the actors)!
From the Main Menu, access the 'Special Features' option. Go all the way down to the very bottom of the menu, and press RIGHT until you highlight the "Cobra's Logo". Select it by pressing ENTER to reveal a video of Goodman talking about finding the easter eggs in the movie. He says to hit ENTER every time he snaps in the film. Try it out!
All easter eggs were generously submitted by phat_tonyca