Depending on your set-up, 2-4 people.
On one site, I'd say 6 is the max (2 in the car, 4 in a tent) ... I've never camped with just one site though, so that might be on the high side.
I say 4 comfortably. Take your tent down each morning for more space during the day.
5/17/15 Ex Hex @ Acerogami
5/25/15 Refused, Turbonegro @ Observatory
5/28/15 Mystic Braves w/Mr Elevator & the Brain Hotel @ Soho
5/31/15 Neutral Milk Hotel @ Ventura Theater
6/03/15 Kiasmos @ Masonic Lodge
8/21/15 Modest Mouse @ Hollywood Forever
8/22-8/23 FYF Fest @ Exposition Park