There has to be. I had seen a promo picture where everyone looked like they were dressed for a prom, and they had the most...I don't know how the say this...um, provocative looks on their faces. Makes me curious!


ETA: A thumbnail of said picture is on the top of the "H" section of http://www.sitcomsonline.com/

There was an episode in the last season:
The Last Waltz

http://www.tvtome.com/tvtome/servlet/GuidePageServlet/showid-1346/epid-31578/

There was another prom one in the fourth season and it was really great. Arvid has three dates to the prom, Vicki, Darlene and one other I think (maybe Sarah). He thinks each of them thinks they are the only one and he runs back in forth between them hoping they won't catch on.