Curiosity might well have killed the cat but it will work in your group's favor if you decide to put on this fundraiser.
Have each of the attendees bring a wrapped package with them, big or small, to be auctioned off. Anything at all can be placed in the package, from tickets to the opera or a hideous-looking lamp that was a Christmas present. You can go some way to disguising the contents of your package if you like. As each one is brought in, add a numbered label to it and place it on a table for viewing.
Give the bidders the chance to examine the packages — picking something up and shaking it is allowed, but there must be no unwrapping or peeking inside.
It's up to you whether you want to run the auction live with an auctioneer or as a silent auction — in the latter case, people write down bids on slips of paper kept near each package and try their best to outbid each other. Include a gew really great items in the auction donated by local stores and let people know what these are to try and encourage higher bids.
Give each of the winners the opportunity to unwrap their package in front of everyone to see if they got a great or terrible prize, which all adds to the fun.
You can read more information about unique auction fundraising events here.
