My Linux workstation had been up for 428 days without a reboot. No cheating, I don't think I even logged out of my X session in that time. But today is a sad day, I had to move my workstation to a new room.
I considered getting a UPS and trying George's Frogger move from Seinfeld. But it probably wouldn't have worked.
The upside is the reboot restarted all the memory leaks, so I'm not using 1GB of swap anymore!