Superbad lives up to its hype. I think Jonah Hill, Michael Cera, and Christopher Mintz-Plasse (the three main characters) do a terrific job -- that is especially the case for Mintz-Plasse, who plays the instant classic McLovin.
In Superbad, Jonah Hill is on a quest to lose his virginity in his last days of high school, he drags his best friend Michael Cera and not so best friend Mintz-Plasse along for the ride. The three are social outcasts.
Jonah's plan involves getting lots of alcohol for all people in this party he was (almost miraculously) invited to. He thinks that if he is able to get this girl drunk he'll have a good shot at lovemaking. The entire movie revolves around this one day in his life.
Unfortunately, Superbad is not so good for the gays. There are a couple of "faggot" slurs used by bullies teasing Jonah Hill. That is not so bad fo us, though: they are bullies who learn a lesson at some point. But later in the movie, Jonah Hill calls Mintz-Plasse "faggol" (sounding like a mix of "fag" and Fogel, the name of Minz-Plasse's character). Nothing really major, but we would be better off without that..."Gay" is also used a couple of times to refer to something bad or tacky.
A potentially redeeming factor would come from the exchange of "I love you's" between Jonah and Michael (we see that scene in one of the trailers). I thought they were going to make out or something, but we get nothing. After the I love you's they sleep next to each other and Jonah Hill wakes up with an awkward attitude, as if he is embarassed by something that might have happened at night.
Also, Bill Hader's character briefly mentions an arrest of a man-she; the reference is kinda neutral to bad (it seems to me, trannies are always being arrested in comedies).