Do personal servers at your own house count? The following uptime is for my Linux box running LFS (Linux From Scratch) on a box that I got for free from a junk pile in the basement of some random Computer store...it faithfully hosts my website.
cbeley--~ > uptime
00:32:05 up 701 days, 7:05, 1 user, load average: 0.00, 0.00, 0.00
cbeley--~ >
do I win a prize? Though...The day that the power goes out for more than 20 to 30 minutes is comming....or the day the computer simply dies...That will be a very sad day
EDIT: If anyone is curiouse, my windows box which I'm using now has been up for about 13 days. I only restart it every once in a while. It's about due for a restart though...