Hi Stuart--Welcolme to the forum. It's been a while since I watched the Carnival episode so I can't place exactly who you're talking about at the moment, but these are the people that are listed as guest stars for that ep:
Mike Grief (as Security Guard)
Steven Ira Schafer (as Gorak)
Joe J. Garcia (as Carnie)
Matthew McGrory (as Lothar)
April Tatro (as Contortionist)
Hopefully this helps. We look forward to seeing more of your thoughts around the forum.