What a great midseason (first semester) finale. Lots of great religion-based humor ("Everyone's religion is weird. Let's stop talking about it"). Loved Annie insisting everyone "say the whole word" and Abed's "I get 72 virgins in Heaven."
Remember in the first couple of episodes when Jeff was seen by the study group as the coolest guy ever? He's not seen that way anymore. It happened so gradually, I didn't even notice. I think it started around the time he lost his apartment and started living with Abed.
The fight B plot was also really good, especially the big throwdown at the end. [Rewatch realization: The bully was ANTHONY MICHAEL HALL?!]
Britta: "The real reason men fight is to release their pent-up gayness." Did I ever mention I like pro wrestling?
I don't know about articles you can look up, but it was done with regular film lighting and cloth light blockers. Just get some bright spot lights and place different colored fabric of various thickness over it untill you get the desird effect.