I had a blast and have ever since been trying to get back to that festival. It is rarely publisized (meaning you have to be in-to get in) nor talked about outside of given circles...I came across this by accident.
Address: 3115 Butters Drive, Oakland 94602. Phone: (510) 531-2930.
Directions: From Hwy 13 Exit Joaquin Miller Rd., take that road about 1/4 mile up the hill, turn Right on Butters & go about 1/2 mile. Look for a small sign and a steep downhill driveway on the right side, taking you to their parking area. A huge outdoor dance floor is on the left, and the clubhouse is on the right. The dance floor has an incredible view of Oakland, San Francisco, the Bay and the Peninsula. Not as much shade on this dance floor, so wear a good sun hat.
Oktoberfest II - Oct 1 - Johnny Krische Band
The fest is 1-6 p.m. Admission around $10.
I would suggest that you come with...It's going to be awesome. Good beer, good food and friendly people.