Hard work pays off
This is an idea that I'm going to use with my son when he turns 4 or 5. It's a game that teaches patience, follow-thru, boundaries, as well as accomplishment without the children even knowing it. It's fun to do, fun to set up, and funny to watch as well.
You'll need to designate an area or room for this game and it will have to be set up before your guests arrive (perhaps the night before).
All you need is a few brightly colored balls of yarn and a bag of piƱata prizes. They sell them at party stores pretty cheap (or you can get fancy and buy things like beanie babies and other toys).
Attach the end of the yarn to each prize and then "hide" it. Leave a trail of yarn back to a starting point and then designate who's string it is with masking tape.
Make sure each child gets a string, and that all of the strings cross over and under one another so that they have to work to find their prize. You can also set it up so that each child has two strings... the first one each child gets a turn finding their prize while the other children route them on, the second string everybody does at the same time. This ensures giggles as children try to untangle the mess of strings.
Lanyard can also be used if you are afraid of one big knot occurring. This is a fun and very different game for children that takes patience and perseverance