One thing I have noticed is that many successful web designers and other consultants do a certain amount of charity work on an ongoing basis. Given that many of these do not need further portfolio development of this sort, the benefits must go well beyond merely building portfolios.
What avenues do I have as a freelancer to take charity work and use it to drum up additional business? Are there ways to leverage charities to make new business contacts or otherwise greatly improve business presence?
Edit: By charity work I mean either doing the the work free of charge or at a steep discount.