I remember that episode. That was long before Charlene came into the picture. Arnold was after a girl and when he brought her home, she immediately fell for Willis. Arnold contronted Willis with it and made him mad.

When the girl came over again, Arnold bought her a box of candy and the girl had brought Willis a disco album. Willis and the girl were dancing to "I Wanna Be Your Lover" and Arnold was making a fool out himself trying to dance. In the same episode, Willis was sitting on the couch listening to Funkadelic's "(Not Just) Knee Deep".

In another episode, years later, Kimberly was working out in a leotard to "Controversy".
[Edited 2/13/05 10:17am]