I usually don't run into problems that can't just be solved using force quit -- this one did eventually go away, it just took a while.

All my machines are set to allow SSH from anywhere, but that would have involved getting up and getting to another computer, although I'm sure my thought process would have started with "Well, I can just open aterm and ssh over to zeus..." or something similar.

Last resort, I usually just go to powerdown on the powerbook rather than trying to bother with SSH and so on.