Dining Options for 100 in Walnut Creek

photo by Flickr user woodleywonderworks

This post from the Chowhound food forums caught my eye recently:

I need to feed 60 high school students + 40 adults on a Thursday night, preferably not too far from the Walnut Creek Marriott. Preferences:

1)Cheap – I need to get out the door for around $15 a head
2)Not nasty
3)Service able to handle a large group efficiently
4)Veg options
5)Any cuisine is fine, but it would be nice if it was somehow representative of the Bay Area

What do people do when they need dining options for really large groups in Walnut Creek? I imagine a restaurant can’t handle this kind of crowd so are there any banquet halls in Walnut Creek that serve decent food at this price?