Alex Lebeck

Alex Trebek (called Alex Lebek on the show) is a game show host, most famous for the show Jeopardy!. He first appeared in the episode "Arthur and the Big Riddle" as the host of Riddlequest. He later made a cameo in the episode "Elwood City Turns 100!" as one of the many guest stars Muffy invites.

Trivia:

 * He, like a lot of the actors in the series, is Canadian.
 * He also appeared in an episode of "Magic School Bus," a fellow PBS Show.