Cuby

Several levels of difficulty, a new map each time.

Pros: simple rules, yet challenging to accomplish.
Cons: too difficult to pass.

It's absolutely free, no registration required,
and I bet you cannot pass the last level without using hints ;)

download: .zip (v.1.1-beta, 22k)

Full version with 3D graphics is expected some day, please check this page later.

There is also a Pocket PC version of this game.