I will do you a favour.

I shall recommend you go and download (for free) Super Crate Box. It recently won Free Indie of the Year (on Bytejacker) and it has casuall sucked up about an hour of my time today without even trying. It's basically a metroid-style platformer, but you're confined to one room. Your little dude has to run around collecting crates, each of which gives him a weapon upgrade. Problem is, it's a randomised weapon upgrade (so you might trade a bazooka for a weak-ass pistol), the enemies you don't kill get faster and angrier, and even if you sit and plug away at the enemies, you don't advance to the next level until you get a certain number of crates without dying.

It's addictive. Play it.

This is the link.