Anyone know which season it is where the 4 main FOL girls goes to the dance with the 4 boys from the boys academy(the dance that also features a slight refrence from the movie "Lords of Dicipline" where each dance couple walks under the tunnel/overpass of raised swords.) I think this is the one, also, where Blair lends Jo her favorite dress for the first time ever.

I think the episode you are referring to is from Season 3, known as "The Academy".

I remember seeing that episode before and from what you've described it sounds like that's the episode, here's a description:
http://www.tv.com/the-facts-of-life/the-academy/episode/5103/summary.html?tag=ep_list;title;21

Thanks! Looks like more reasons for me to get season 3 in October, now.:D

Yeah, I think that was supposed to be a spinoff for a sort of male version of Facts. I don't mind that one though. There are some funny moments.

It is a pretty good episode, but certanly not one of my favorites.