Had a good time investigating this:
OpenType Font File causes Windows to crash.
Microsoft hasn’t acknowledged the bug’s presence, nor have they issued a fix. So right now, if you’re running Win2K or XP, you’re vulnerable. In my case I was able to lock up a Win2K machine so badly that it refused to ever boot again, claiming that some device driver was missing or corrupted.
Whee! Go Microsoft.
Update: (08/25/2003) This is repaired in Windows 2000 Service Pack 4. I can’t speak for XP.