Every 4th Sunday, the Bluegrass Association of Southern California (BASC) hosts a Jam in The Park in Encino.
Real friendly folks, real friendly atmosphere. There is a park nearby where kiddies can play (though not within eyeline while you play).
If the weather is nice, it's outdoors and if not, pleantly of room indoors.
Bathroom for free...sodas and snacks for $1.00 each. The jam is free. This is a great place to meet some of the most active Jam players around and to get a bit more involved in the "Bluegrass Scene" in SFV.