I just had to hard reboot Gir. Given the way that I work with him, this is a more problematic thing than you'd suspect. Sure, it gives me an opportunity to run Software Update and install the updates that require a reboot (Quicktime and OS X), but it's annoying as hell and I'm certain to lose a bunch of stuff that I was doing in Safari.
(Yes, of course I still love him dearly. The joy he brings me on a daily basis just makes the minor hiccups stand out that much more.) :-)