Kind of off topic, but one big problem with volunteering is that you end up doing work that ought to be paid for. Working alongside staff doing the same thing as them is just not right.

When I volunteer for an organization I want a list up front of activities. I also want to know how they acknowledge the unpaid work by alternative remuneration. Example if I were working everyday at a festival I'd expect a ticket to a show. The museum I volunteer at gives me free admission to my guests and a pretty deep discount. All this goes to what I spoke about above - ACKNOWLEDGEMENT and APPRECIATION.