yeah, i applied to only two and got ripped off too!
What I did was submit references that can verify my involvement in a number of my activities. On OUAC, you aren't giving them a detailed description of anything. If I remember correctly, it's basically like title and date. I don't think there was a description for anything.
So in your case, it's like Kerry Campaign - Volunteer Summer 2004. Just put the name of someone that knows you did that (that isn't a member of your family). Like a co-worker or a friend or someone who can verify it. Even if you give them the name of the guy in cinnicinati, and they call, and he isn't there, then who cares. It's not your problem.
If it was a 'real' resume, then you should probably take it a bit more seriously - but its not. For work experience, I put down my managers. But for volunteer experience and activities - i just put down people who i thought could sufficiently verify my involvement.