I'm looking for websites where volunteers can sign-up to provide and item and/or to work a shift for an event.

I tried Doodle, but the options are too limited and I can't get a response to my questions.

I also registered at mysignup but the site continues to give me error messages when I attempt to sign in despite the fact that I followed the confirmation link they gave me via email.

Are there any other websites out there to facilitate sign-ups for events?