I have to say, Celebrity Haunted House Paranormal Project (watch it on Hulu) makes a great summer night popcorn show. I guess there were only six episodes that aired back in 2006, which is kind of a shame.
This episode featured Olympic ski racer Picabo Street, Baywatch star and supermodel Michael Bergin, actress Mariel Hemingway, actor Joe Piscopo, and Real World: Chicago start Tonya Cooley. Of these, Picabo Street turned out to be the hard-core believer, while Joe Piscopo was the laid back skeptic. In fact, Piscopo seemed actively bored at several points during the show.