What to do with linux laptop?

Hi guys. I just installed Xubuntu on my old laptop (1.3ghz, 256mb ram, 40gb hdd). I intend to use it as a learning experience and play with setting up a home network. Problem is, I don't know what fun things I can do with it. Right now. I'm using it as a torrent leeching machine and an ftp server. I have 2 more system connected to the router, one is my sister's laptop and the other is my main PC.

Any advice? In b4 share porn with sister.

Install Vista.