Don't be the last one to have your hat on. A great party game.
Hats for everyone. Yarn necklaces.
This is a great party game to play throughout a party while other stuff is happening. When each guest arrives give them a yarn necklace. This indicates they are still in the game. As each person gets eliminated, they give up their necklace. Also give each person a hat to wear. These can be all the same or different. Perhaps you can match them to the theme of the party. Instruct everyone that when the host removes their hat, they each need to remove their hat as quickly as possible. The last person with their hat on is eliminated and they must give up their necklace. Then everyone puts their hats back on and the party continues into the next round. A bit later the host removes their own hat again and the rest of the players do as well. Again, someone is eliminiated.
The when the game comes down to the host plus two players, the last round starts. When the host removes their hat, the player who removes their own hat first is the winner and gets the prize.