Need a new project! what can i use an old P4 desktop for?

[lmfy2k]

running a network at home,

have an old pc running ipcop as a firewall which works a treat, got another box running Freenas - also works a treat

i have one more old pc that i want to use for something

we don't need a home server of any kind though, so is there anything i can use this old pc for?

thanks!