Rebooting a web server remotely using iisreset
This one surprised me a lot when we found it. You can reboot a computer that is running IIS remotely by running the command:
iisreset [computerName] /reboot
It's been very useful today when we've been patching a whole rack of servers with security patches, but could be very dangerous in the wrong hands :-)
There are a few more interesting options available. Do iisreset /? for more details.