First of all, happy birthday to my husband and best GM ever, Matthew McFarland! *muppet arms* Yaaaaaayyyyyy!!!!
Whoo boy, this one's hard. I think -- I think -- that the current title holder has to go to our monthly Monsterhearts campaign, which has been running for two years almost exactly. I player Briar Rose Stephens, who's a Chosen that lives with her absentee single professor dad and a housekeeper in Perdido, CA. Briar's boyfriend is Austin Fairchild, whom Matt has been trying to kill off for like three seasons now. She owes a life to the king of the Fae, and she looks at it as a personal responsibility to keep Perdido as free from the threat of monsters as possible. She's about to graduate high school, though, so who knows what will happen? :)
Prior to that, it was the bi-weekly Changeling: the Lost campaign, titled Snowblind (which I don't have an easy link for, but I'll work on finding one and updating it), which I started guest-starring in before I even moved here, during my long-distance-relationship phase with Matt, and it lasted another 2 years after I got here.
I will play short games, but really, I much prefer longer ones. I don't need to advance my character all that much, I just want the character development. That said, though, it's hard to get one going, and Matt has so many games that he wants to play and run and test that it's a difficult thing to get a game that really goes long enough to suit my taste. We can compromise, though. :)