Kevtris 2.0 from Caywen is a free block-dropping game for Pocket PCs with nice graphics and customizable controls.

Kevtris 1.1 by Caywen is a free Tetris clone with nice graphics, customizable controls, and is very addictive.

Dots 1.1.1 (GameBag One) from Ilium Software is a free Pocket PC game. Play this casual game at the airport, in waiting rooms, or in meetings. Just don't get caught!