I've been a member of the Kew Gardens CSA for three seasons now (and in fair disclosure, also have…read morevolunteer for the 'core' group to help out as well).
What I like about the CSA is that it gives you a means to support your local organic farm (in this case, Garden of Eve on Long Island, NY) and an opportunity to meet your friends and neighbors and to build up your community together.
I've never been much of the cooking type and can't follow a recipe to save my life -- however, through the CSA I've been able to acquaint myself with new and fresh produce and acquire a much better understanding of how availability can change seasonally and by crop.
The variety of food you might get in a share on any given time is pretty incredible. Over the course of a season (Spring / Fall / Winter) you're likely to receive a mixed variety of the following:
Tomatoes, carrots, potatoes (Idaho, red, purple), sweet potatoes, cabbage, celeriac, daikon, onions, garlic, butternut squash, cucumbers (regular and "lemon"), basil, brussel sprouts, broccoli, radishes, rutabagas, mesclun lettuce, mizuna, mustards, bok choi, escarole, raddichio, scallions, Swiss chard, collards, mustard and other greens.
Of course, if you haven't encountered any of these before in your supermarket, part of the real fun is sharing recipes and cooking tips and learning from your fellow CSA members how to prepare them.