I'm getting error 500 on every endpoint on questions method (with key):
http://api.superuser.com/1.0/questions?sort=votes&pagesize=30&page=1&key=stackprinterkey
the only endpoint not affected is stackoverflow:
http://api.stackoverflow.com/1.0/questions?sort=votes&pagesize=30&page=1&key=stackprinterkey
key parameter is the first suspect.