Rarely has there been a comedic ensemble as good as Seinfeld's, mainly because the show allowed the four protagonists to team up differently every time. The most hilarious proof of this is The Tape, which features the best pairing of George and Elaine ever conceived in the series' nine years.
Remarkably, the episode focuses on pretty much one single storyline: with the exception of the bits where George orders hair-growing cream from China, the narrative is constantly occupied by the guys' reactions to a dirty message a female fan left on Jerry's tape recorder and George's adorably ridiculous infatuation with Elaine when he discovers she's the one who did it. This leads to some incredibly embarrassing moments when he has to explain the situation to jerry without revealing the whole truth.
Aside from her acerbic wit (always sharp as a state-of-the-art razor), Elaine's best quality is her sex appeal, and the show's writers always knew how to exploit it to great comic effect. For a good example of this, look no further than the scene where she reenacts the dirty talk in front of an unsuspecting George (if only all moronic sitcom sidekicks were like him...), or the perfectly timed epilogue, with all four main performers on top form. Although it's Jason Alexander who, as usual, gets most of the funniest scenes, the episode is in fact dominated by Julia Louis-Dreyfus, body and voice (sorry, I just had to say that). The only scene that comes close to her standout effort without her being in it (for the most part, at least) is when Jerry and George engage in a weirdly funny conversation about the habit of saying "hello". Priceless, as always.