Edit: For non-svn-enabled web hosts. (Owen)
I spent about an hour last night writing a quick and dirty bash script to download and upgrade the nightly version of WordPress of this every night. It grabs the current file, extracts it, copies it to my nightly directory, and runs the upgrader. I amaze myself sometimes. I’m not referring to me doing this, but the fact I wasted about 30 min figuring out why it was telling me the .tar.gz was corrupt. I had made a typo and was curling the error page instead of the actual archive. Ooops!