Ok kids, we have a lot to cover here. Sue Sylvester in love? Rachel and Puck making out?! The Thong Song?! Really???
Mashup was all about in-congruency. This was summed up best by adorable Emma when she told Will that the two wedding songs Will was trying to mashup would never ever go together even though they are "both great songs." This was a not so veiled allusion to her doomed engagement and Emma and Will made googly eyes at each other while they processed the weight of that statement.
In Glee-kid land, the tables were turned as well. McKinley High's self-proclaimed "It" couple were welcomed to the "new world order" with a slushie facial courtesy of hockey player Karofsky signaling their descent into unpopularity. Desperate to regain their status, they turn to the world's most prim guidance counselor for advice resulting in the pair wearing sunglasses for the rest of the episode in an attempt to look cool. Turns out, the popular kids don't care about their sunglasses. They outcast Quinn and Finn for their association with Glee and Quinn's unplanned pregnancy. Will popularity and Glee ever go together? Not quite yet it seems.
Ken spots Emma and Will in a tangled embrace after Will's spirited performance of the "Thong Song". (What exactly was he doing there? Wasn't he supposed to be teaching her how to dance? Oh, I love the contrived situations they create to show off Matt Morrisson's dance skills. Priceless.) Ken gets back at Mr. Schue by scheduling a mandatory football practice during Glee rehearsal. That's cold Ken! All of the Glee footballers choose Glee except *shocker!*, our hero Finn. He just can't handle being uncool. Ultimately, he gets Ken to relent by performing his own version of the "I have a dream..." speech. Finn has a dream that someday he will live in a world where a guy can play football and sing and dance too. For now, he does.