FMSC is a faith-based humanitarian organization which packages and sends food to global areas affected by famine and war. They do many secular organizational and corporate events in which groups sort, weigh, and package grain for transport for a specific number of hours. it's hard work, but a ton of fun.
Info is here. http://www.fmsc.org/page.aspx?pid=260 I've done their events with the military in the past and they're hard work but a lot of fun, and no religious affiliation is required.
While they do look for some token donation from people who participate, by no means do they.
Since this is a charity event that relies on our work, please be fairly certain a couple weeks out you can go, or cancel your RSVP in advance.
(No sandals or flip-flops only for volunteers working in the warehouse).