Here is a great game, especially for winter.

You'll need:  some sort light weight bowl like a flat Tupperware dish of some sort.  20 or so cotton balls and a spoon.

Tell each guest they have to hold the bowl over their head with one hand and with the other they hold the spoon and with one or two tries see how many snowballs they can scoop out.  They have to use their hand on the spoon and cannot use fingers to help hold the snowballs in the spoon.

You cannot tell when you have cotton balls in your spoon. 

For a joke you can first give them a baby spoon to use!  Then give them a regular spoon, or pick out one guest to play the joke on and when it comes to her say "wait, oh I forgot, we were supposed to use this spoon!' and hand her the baby one.  Let her try and then say, "well since I balled it up in the beginning, we'll let you use the regular spoon too" and continue the game.  Give prize to one who gets most.