We're one day late on this one, but rather than brightly colored hidden eggs for Easter, in this case we're of course referring to "easter eggs," little secrets that programmers hide in their applications and code. Macworld has a great roundup of four easter eggs hidden in popular App Store apps, from a secret edition of the 1926 Kelly Blue Book in the official Kelly app to the funny result you get when searching for "tilt" in Mobile Safari.
Off the top of my head, the only other app easter egg I know of is the fact that you can play with the various characters wandering around the title screen
