I've joined a writing group that meets on Monday nights. We had a bit of trouble getting it off the ground last fall, but now we are meeting fairly regularly and having a blast.
Our lovely hostess termed the time we get together "writing shabbat," as it is a time for everyone to step away from their daily life and use their creative mind with no pressure at all. It is very casual, usually consisting of writing prompts, timed exercises, and lots of good conversation about writing, books, and storytelling.

If we have enough people, we will do an "exquisite corpse" exercise. The point is to collaboratively work on a piece of fiction with having little or no guidance regarding the story. We take a prompt, such as "directions for a product originally written in a foreign language," and go from there. Everyone writes a line or two then folds the paper so that the next person can't see the entry, or only one line of the entry. We'll make two or three passes and then read them aloud. The responses are always hilarious and have the whole group laughing. The exercise is a wonderful way to get relaxed into writing--it takes off all the pressure to get it just right.

I've been looking for a writing group for years and am so grateful now that I've found some kindred spirits to write with. Monday nights have never been so much fun.