I heard on the Ravely Bay Area Knitters Board that there's a knitting retreat at the Quaker Center in the Santa Cruz Mountains in early January. There aren't any teachers or anything -it's more of a hang out and knit thing, but for $240 at the Quaker Center it's a getaway that can't be beat. It's only a $100 deposit. I'm seriously considering attending.
For Saturday only attendees, you can arrive as early as you like and stay as late as you want. Breakfast and dinner on Saturday are included. You can sign up for a massage and join in the gift exchange game (where everyone brings a wrapped fiber related gift and the gifts are stolen and traded throughout the game) Saturday afternoon.
For the entire weekend attendees, the retreats start on Friday with an optional yarn crawl, where we visit various yarn stores in the bay area and have lunch together. We end up at a coffee shop after shopping at Cost Plus.
At about 4:15p we drive up to the facility (the Quaker Center in Ben Lomond http://www.quakercenter.org/) and stay there until Sunday. Note: This retreat is not associated in any way with the Quaker Center and there are no religious activities, we merely rent their facility.