I've been playing around a lot the last few days with Pandora, a website that lets you create little radio stations by entering the name of an artist you like; it automatically selects tunes by that artists and ones it considers to be similar. Usually I listen to my iTunes library while I'm working, but this is a way to listen to some things I don't yet own for a change. (And since I seem to spend hours at the computer, variety is nice.)
I think if you click on this link, it will take you to the mix I've got playing now. If you listen to music on your computer frequently, Pandora seems like a free service worth having some fun with.