Installed plan9 recently. It really has loads of wonderful ideas that I sorely miss in other systems. Still, it doesn't fill enough of my needs to do much anything with. At least there's still quite a bit to learn there and it looks interesting.
Oddly enough my OpenBSD/sparc firewall also threw a panic the other day. Didn't find the energy to report that. Just noted that the console was showing a debugger when I turned the terminal on. After reboot, it has been running fine.