Stack the log is one of those games which becomes blazingly addictive the more you play, involving stacking a bunch of logs on each other.

http://xwuz.com/stack/game.html

Knock Out is an iPhone version of the classic NES game Punch Out!

http://www.gyrocade.com/ko/

Magic iEight Ball responds to your questions by you simply rotating your iPhone.

http://www.ieightball.com/

Battle Ship on your iPhone!

http://www.rogerkenny.com/battlefleet

Carmadillo is a game reminiscent of Frogger from the old days. It runs in Landscape mode, and is actually pretty addictive…

http://mynumo.com/iphone/carmadillo/carmadillo.htm

Bowling on your iPhone!

http://mynumo.com/iphone/ibowl/ibowl.php

Classic Tetris, now on the iPhone.

http://iphone-tetris.com/

Baffle! is a game where you must align the board so that each row, column, and major diagonal contains 1 piece of each color and 1 piece of each shape.

http://bafflegame.com/iphone/

Classic Duck Hunt on your iPhone!

http://www.orangeburgyoungprofessionals.com/duckhunt/hunt.html

Chess clock is a simple chess clock for your iPhone.

http://www.bottletown.com/chessclock/