Who is Kimberly from Geography Club and what is their importance?

Kimberly is the girl that Gunnar has a crush on and asks out. It seems as if Kimberly doesn't really like Gunnar, but is just dating him so that her friend Trish can go out with Russel. Kimberly is loud and obnoxious. She drinks too much as well. Kimberly is one of the girls that spreads the rumors about Russel being gay.