Misc: how many gallons are in a barrel of oil??

Questions

Name the sitcom that featured Judd Hirsch, Andy Kaufman, Tony Danza and Danny Devito.?

David Hasselhof spent most of his time driving a car on which eighties tv show?

whose character name was also the title of the show?

"And knowing is half the battle"?

Who got slimmed first in Ghostbusters?