LAIFC has foil on Monday, Wednesday and Friday nights. Things usually start going around 7:30... some of the kids start earlier.
Wednesday night is a tournament. Usually 15 or so people. Also, right now, there is informal gathering on Tuesday and Thursday, although I have no idea who's going to be wandering in.
Beverly Hills FC has their foil on Tuesday, Thursday and Saturday. They've always been very good about emailing me back right away when I've had questions about times and such.
Swordplay in Burbank is another option... not sure about their foil times though.