I saw this today on a wedding featured here on Offbeat Bride, and I love it.
They made buttons for all of their guests at the reception. The wedding party & family members had buttons with their "title", and the rest of the guests got to choose what they wanted. Things like "Bouquet Dodger" (that would've been me) "Starving Actor" (we'll need a few of those) and "I'm a little drunk" (ditto) ... so hilarious. I know that button makers aren't too terribly expensive. If we have leftover funds for the reception, I totally want to do this.
Above image from the bride's Flickr stream.