Just setup a small VPN between my machines between a couple different networks (RPI Dorm, RPI ACM Lab, Home) with CIPE. Standing for Crypto IP Encapsulation, it allows you to establish PPP links between boxes using encrypted UDP packets. Really cool! I can play Quake III over it, encrypted! (Okay, that wasn't the best example, but I'm sure you can think of a better one)
Maybe I'll write a small howto in the future, but for now, there are still a number of issues that need to be worked-out. Mainly performance, since stuff like SMB is awfully sluggush...
