What can I do with an old PC?

I'm a mac user, and have been for more than 5 years. However, a friend gave me an old PC (Dell Optiplex 360, 1GB of Ram, Celeron processor), and I have no idea what to do with it. I'm thinking about hooking it up to my TV, but I really don't know.

Seriously vergers! What should I do with it? Make a NAS? Trash it? Eat it? Hack it?