Then you may like Minecraft, which I usually play at work during my lunch hour on my little Netbook-that-could.
Minecraft is a sandbox-style game, which means that you aren’t following a set story or plot. There is nothing in Minecraft that you *have* to do, unless you’re playing Survival mode. There are two ways to play- Creative Mode and Survival Mode. Personally I like Creative better because I don’t like fighting monsters, I just want to build houses and dig underground fortresses out of the landscape. Survival mode is exactly what it sounds like- you have to fight to survive, because every night creatures appear to kill you. There are so many things you can do with this game- I find it helps that I have a time limit, because otherwise I’d play all day and not notice I’d forgotten lunch and breakfast somewhere in those hours of staring at the computer… definitely an addicting game.
And if you like the game, then you might like some of the texture packs available for it. Personally, I like this site (Painterly – click here), which allows you to customize your own pack from their pre-made selections.