Playable games on a Netbook?

I'll kick it off with Minesweeper.

I would image GTA 3 would also work well. SA can be buggy at times, but your hardware might not hold it back.

Some of my favorite low hardware req games are:
Diablo 2, Torchlight, Tropico, Most of GoG's catalogue, Civ games, might need to go back to around Civ 3 for it to run smoothly, Sim City 4, Binding of Isaac, Dungeons of Dredmore.

Torchlight has a "Netbook mode" in options and most probably it isn't a joke.

Torchlight works ok
Same with BoI

Tropico Reloaded.

Depends on whether you're looking for Steam games only or if you can live with non-Steam ones.

tetris

Dont Starve :3

Pinball

Super Meat Boy, BIT.TRIP.RUNNER, Castle Crashers, GTA all to Vice City, Half-Life, Counter Strike.

Those games i tryed in a netbook and run very good :)