Boulder has a number of farms which provide a farm share (also called CSA).  This book gives you a high level overview of all the different kinds of CSA shares.

CSA, which stands for Community Supported Agriculture, is a system for helping farmers sell direct to consumers. Consumers pay at the beginning of theseason, when the farmer needs capital most (for seeds, fertilizer and other seasonal startup costs), and receive farm raised goods later that year,typically on a weekly or monthly schedule. CSA programs are also called farm shares, because consumers are buying a share of the farm's production. Thereis also an element of risk sharing--the crop is poor, share members agree to receive less; the converse is also true--the farm produces a bumper crop, share members will get more.