One of TV's classic sitcoms, "Happy Days" marks its "30th anniversary" with an ABC special at 8 p.m. tomorrow (KOMO), even though it debuted in 1974.

Here are five things you might not have known about the show:

1. Arthur "Fonzie" Fonzarelli was to be named Arthur Maschiarelli (creator Garry Marshall's real last name) and nicknamed "Mash." ABC had Marshall change the character's name because the network felt "Mash" might remind people of "M*A*S*H," a popular show on CBS.

2. Both Micky Dolenz and Mike Nesmith of The Monkees auditioned to play Fonzie.

3. Robbie Benson and Don Most were both considered for the role of Richie Cunningham. The character of Ralph Malph was created for Most.

4. Richie Cunningham's favorite song was "Blueberry Hill" by Fats Domino.

5. The house used for the exterior shots of the Cunninghams' "Milwaukee" home is situated at 565 Cahuenga Blvd. in West Hollywood.