ÜberGameLord, John Carmack (the dude from id software, DooM, Quake, ...), has made a little demo for the QuakeCon 2010 show, of his already amazing new megatexturing technology and displays his utter godliness by making id's upcoming game Rage run on an iPhone4 at no less than 60 frames/second (and apparently, it runs fine on older iPhones too):
Carmack shows Rage running at 60 FPS... on an iPhone (techreport.com)
For a more detailed look at Rage: http://ragegame.net/