We may have some downtime this weekend.
The reason is that I will be moving the site to a dedicated box. The move of the files and database should be pretty seamless (famous last words) but propagating the name server information when you do a server move tends to be sporadic over the first couple of days after you make a change. I'll give some more specific updates once I'm a little more sure of the date time that it'll happen.
The benefits of being on a dedicated box are speed, stability and I won't be sharing resources with 500 other sites.