1) Abbreviation for the television show Gilmore Girls, in which a mother and daughter do quirky things in their small town. Sounds stupid, but is very good.
2) Abbreviation for the television show Gossip Girl, in which a bunch of rich kids have sex and buy things. Sounds stupid, is stupid.
Person 1: I was watching GG last night-
Person 2: Oh, I saw Gossip Girl too!
Person 1: Hell no. I was watching Gilmore Girls.
Person 2: Oh...
Person 1: Get outta here.