Orange Fun is a massively popular Tetris-like game. Blocks, shapes composed of 4 blocks each, are falling down the screen, and one has to direct them so they will fit to the wall on the bottom. When a line of blocks has no gaps, it disappears!
Jigsaw Blocks is simple to learn yet challenging. Slide rows and columns to reconstruct various images. Increase the number of blocks and increase the challenge.
Escape is a tile-based puzzle game in the style of "Adventures of Lolo" or "Chip's Challenge." Unlike either of those games, Escape doesn't rely at all on reflexes--it's all about your brain.
A turn based, multiplayer, play by e-mail war game. As large a group as you like can play at any pace the group decides on. (e.g. from one turn a week to several turns a day.) Each turn typically takes only a few minutes to play.