Dorie Barton was not part of the original cast. She was introduced as Tess, Henry's girlfriend, in the second episode of the first season, and wasn't added to the opening credits until the third or fourth episode of the first season.
Ian's dog is named Edgar.
The role of Maddie was originally played by Jessica Cauffiel. In late August of 1999 Heather Paige Kent assumed the role.
Lyrics of the theme song
Batty, bonkers, crazy, loopy, loony, hazy
Chaotic, neurotic, peculiar and amazin'
Demented, deranged, particularly strange
Frantic, raving, shaky, flaky
Making me insane