A wonderfully simple and horrifyingly addictive game for win32, written by Nozomi Matsuzaka.

In moon, you are a sleeping1 fish.
|\    /   \
| \  /     \
|  \/  \_/  |
|  /\       |
| /  \     /
|/    \___/
The fish follows the mouse pointer, but has a maximum speed and can't always keep up with it. Lots of stars enter the screen, traveling at various speeds and angles, but always downwards and left. In the corner a timer steadily counts up. As it progresses, the stars become larger, faster, and more numerous. A soothing midi file plays in the background2. When the fish collides with a star, the music stops, the game is over (and the fish dies).

Important milestones:
0 - start of game
2500 - larger stars appear
4000 - Enormous stars appear
5440 - My current high score3
69396 - the world high score, as of a few years ago.4

Moon works best when you're not concentrating. Just play it forever until your mind is blank :)
Stars can pass through the fish's tail without injury. It's just the head you have to worry about.
Surprisingly, moon is just as playable with a touchpad or accupoint as a mouse. Perfect for airports! I'd appreciate expermental data from anyone with a tablet PC.

Moon is availible from the author's homepage at http://www.ymo.net/~nozomi/works/Moon/

1 - You can tell it's sleeping. It has its eyes shut.
2 - The moon ringtone, for nokia 'phones:
Tempo:160, Scale:6, Note duration, 1/4. Copy and paste the tiny line below:
2h5.,a5,c,h5,2g5.,2d5.,e5,f#5,g5,d5,f#5,g5,h5,c,h5,32a5,32h5,8a5.,g5,a5,2h5., a5,d,f#,2g,a,2h.,c7,h,a,g,f#,a,2g,16d,d,f#,e,c,2h5.,a5,c,h5,2g5.,2d5.,e5,f#5, g5,d5,f#5,g5,h5,c,h5,32a5,32h5,8a5.,g5,a5,2h5.,a5,d,f#,2g,a,2h.,c7,h,a,g,f#, a,2g,d,2g.,8f#,8f#,f#,f#,f#,d,a,g,d,h5,g5,d,g,8f#,8f#,f#,f#,f#,a,c7,8h,8c7,16a., 16h.,16a.,8g,8a,g,d,e,8f#,8f#,f#,f#,f#,d,a,g,d,h5,g5,d,g,8a,8d,a,h,16c7.,16d7., 16c7.,h,a,g,d,h,2a.

3 - Someone's got to have done better than this... feel free to sumbit your high-scores for the E2 moon top 10.
4 - Moon used to have a high-score table (http://www.ymo.net/~nozomi/works/Moon/ranking.html), but it appears to be no more.