The Celebrity Lie: Marcia boasts that she can guarantee that Davy Jones will play at their junior high dance. Not knowing his actual schedule or how far in advance he books engagements, or whether he'd even consider playing a gig for junior high students. (In real life, many celebrities have likely gotten letters from enthusiastic teenaged fans hoping they will make personal appearances at their school ... only to be shot down by (semi-polite) refusal.)
Here We Go Again!: A very similar plot would be replicated two seasons later, albeit this time with Bobby and Joe Namath instead of Marcia and Davy Jones.
Hilarity Ensues: Marcia is lucky that Davy Jones by all accounts a nice guy, and he did it more than just because of that reason agreed to play at a junior high prom. In the real world, Marcia might be accused of stalking Davy Jones and possibly arrested at either the recording studio or the hotel where Davy was staying. Certainly, she would not have gotten by security at the recording studio, and in the very least if she did try to make a move she'd be escorted out and not so nicely and then forced to admit she couldn't make good on her hasty promise to procure Davy Jones. (This would be true with or without Davy's input.)
Special Guest: See episode title to find out which famous Monkee starred in this episode.