Balderdash is simple, fun, and lets everyone get involved. You'll need a dictionary, paper, and pencils and around 5-10 people, so at a big party you could make several groups.

Each player gets a pad of paper and a pencil. One player gets the dictionary as well. The player with the dictionary finds a difficult word, and tells it to everyone. Each player then writes down what they think is the correct definition, while the person who found the word writes down the dictionary definition. Then, the player with the dictionary collects all the definitions and reads them. Players try to guess which is the correct definition.

You get one point for guessing the correct definition, and one point for each player your definition fools.