Centerpiece giveaway: musical bags
Take several paper-bags (one per table) and fill them with some items, such as a coin, a paper-clip, clothes-pin, a card etc. Every bag should have the same amount of items. It is best actually not to mention that this is going to be the giveaway of the centrepiece.
The next part of the game is very similar to playing music chairs. Play some music and have the guests hand the bag around the table. Whenever the music stops, the person who is holding the bag at the time, grabs one item from the bag, without looking into the bag. This continues until the bag is empty and someone is just holding the bag. That person gets to take the centrepiece, and put it into the bag to take home. The others get to keep the items they took out of the bag.
If this is presented well enough, people will probably end up trying to avoid holding the bag for too long, which makes it a funny and entertaining game.