Frets on Fire is an open source version of guitar hero that you can play on your home (read as: work) computer using your keyboard instead of the guitar.
The program comes with a few standard songs, but you can actually use an included tool to import all the songs from Guitar Hero 1 and 2. Or, if you’re feeling particularly compository, you can make your own using the in-game song editor. Now you can finally wail on “She Blinded Me With Science” like you’ve always wanted. Live the dream.
Also, you can customize your character alla Tiger Woods PGA Tour giving them whatever hair and clothes you want. It's not quite as advanced as Tiger's, but for a free game it's stellar. Happy hammer and pulling.