Hoople - 3:22 pm on May 3, 2012 (gmt 0)
+1 to Frank's suggestions. I'll add 'do it, NOW!'
Long term there are remotely manageable AC power strips that you can log into and power off/power on the server from a remote telnet session.
There are keyboard/mouse over IP solutions available too that can send CTL-ALT-DEL to the server.