Mobile Voter is making it easy for people with mobile phones and time on their hands to volunteer:

In 2008, we’re going boldly into the future of volunteerism! Have you ever spent 20 minutes waiting for your train with nothing to do? Or unexpectedly had the afternoon off? Have you also wished that you could give back to your community without simply sending a check or going through a laborious membership signup process? What if you could, spontaneously, volunteer your labor or expertise? Our “Volunteer Now!” project intends to enable this kind of on-the-spot volunteerism by connecting you, via your mobile phone, to volunteer opportunities in your immediate vicinity – or to organizations that can use your expertise over the phone.

A scenario: You’ve just missed your airplane and have 6 hours to kill at the Philadelphia airport. You click the “Volunteer Now!” button on your mobile phone. It asks you how much time you have. You answer “4 hours” and it returns a list of relevant matches. It knows that you are a business executive with a specialty in contract negotiation, so the first match is from “Pit Bull Rescue,” which needs someone to review a contract for a new kennel facility. Your profile history also shows that you sometimes enjoy good old hammer-swinging physical labor. The second match is from “Wister Middle School,” which is 2 miles from the airport and is having a volunteer cleanup day today.