Do you regularly have clients who need developers for one-time development projects (kind of like a reverse elance.com), or is it strictly for Monday through Fr

Do you regularly have clients who need developers for one-time development projects (kind of like a reverse elance.com), or is it strictly for Monday through Friday full time work? I would love to do small side projects for others, e.g. on weekends, but bidding on projects on elance, odesk, etc is a headache I would certainly pay A LOT to able to skip. If not, does anyone know of a service that does this?