I'm sort of stealing this from the Moms&Maids board. I grew up w/one younger brother, who is almost five years younger than me. The closest thing I ever had to sisters was my sorority sisters HA!
FI's brother is dating and now will be having a child w/a girl who may eventually be my SIL, and if nothing else I'll be her childs' aunt. She is 21 (I'm 27) and we really don't have much in common.
I'm just curious to know what kind of relationships others have with their SIL's or FSIL's? Do you get along? Do you hang out? FI and I go out rarely w/FBIL and the gf but I've never hung out w/her alone.