[Update: iPhone users should check out the free and amazing “Papijump” game in the iTunes app store. It’s basically the same thing as snake jump but making ingenious use of the iPhone’s accelerometer to control the character]
When I was still rocking my Palm Treo (an absurd cellphone-palmpilot-camera gadget) I had one game that actually kept me playing and had my friends grabbing the phone and trying to beat my score, SFCave (Internet Version, PalmOS Version). The premise was simple almost to the point of being mathematical (which I guess describes all the old Atari games as well). You’re a parabola that is falling, the one button makes you go up but will kill you if you hit the roof and you have to navigate through an increasingly narrow cave-path. Something about just having one button and the way the parabola is drawn just makes it a ton of fun despite the fact that it is effectively a one dimensional game (up/down).
Searching for snakes for some reason I came across this upgrade to the premise, Snake Jump (pictured above, works without downloads or anything), which adds a whole other dimension! Allowing you to move side to side and kill some bricks or something. Needless to say, you will be hypnotized.
Bonus: You can’t possibly spend more than 20 minutes on this. Praise games that lack life-destroying potential.
(If anyone with windows wants to try the THREE DEE version, I’d love to hear if it’s as fun)