This is really strange. I upgraded a blog today to WP2.61 and everything was working fine. Later on I see that the site appears without styling. Furthermore, the Dashboard has no styling and even if I change to the default theme, the problem persists.
Even more strange: the same problem occurs on a different blog (both installed using Fantastico scripts in CPanel) that is using WP2.51
Also this one: http://valleymechanical.com/
Finally, another blog on the same server has no problems: http://yourcustomblog.com/
How did several separate installations get corrupted?