Tabitha
Britney-Philiac
It'd be interesting to have Morgan Spurlock but I doubt that would be a particularly good execution.
russell brand played himself in a recent episode that should making be its way across the pond soon
angry dad the movie
I'd like to see Trey Parker and Matt Stone guest star as themselves. Their appearance as interviewees in the 20th anniversary special is one step closer.
I would wanna see Will Ferrel and Liam Neeson, but it would probably be funnier if they were fictional characters, not themselves.