It's funny, I read one time that Keifer heard some college kids had a drinking game where they took a shot for every time he said "DAMN IT!!!", so during the next episode he ad libbed many extra "DAMN IT!!!"'s for them though they weren't in the script
I've always liked Keifer, he and his dad are both awesome actors. Keifer's a pretty laid back dude too it seems. Isn't he in a band? I saw him traveling with some band over in Europe on tv the other night. It wasn't clear what his role in the group was though.