Cubical puzzler, simple but fun until you reach your frustration limit :P
Gluey is a small, physics-based puzzler built in flash. It revolves around differently colored blobs that the player has to "pop" to gain points. It's pretty simple but it's smooth graphics and feedback just pull you into the flow. Especially the Zen Mode is great for killing time.
Linear RPG is a small little pardoy game that makes the structure behind JRPGs visible. It's pretty easy to play, just walk left and right but it looks goregous and is entertaining for the brief time it lasts.
A historical strategy game detailing the events in England in 1066. You can play a short (3 battles only) campaign against the computer. Here you'll learn something about history and find a feel for the mechanics. Then you can either play skirmish battles or fight against other players.