Movies
Assemble a list of 20 well-known movies and place the titles in a hat or bowl that each riddler can draw from. It is important to stick to well known movies, big blockbuster or award winning films, to ensure at least a few members of the team will have seen the film. Movies are a fun category because there are two different ways to act out the movie: either by relaying a memorable scene from the film, or by acting out the words in the title of the film. For example, the movie "Big" starring Tom Hanks could be acted out by either conveying the sense of something being large, or by acting out the famous dancing on the large piano scene.
Historical Events
Acting out historical events in a game of charades is definitely not for the weak of heart and mind, as it is a complex and challenging category. However the complexity is precisely what can make it so entertaining. The historical events should be prominent enough that the players guessing would likely have some knowledge of their existence. The event can be acted out by replaying what happened or by acting out the words in the event. For example, the sinking of the Titanic could be acted out by paddling, or recreating the famous "King of the world" scene from the movie.
Holidays
Holidays are fun to act out during charades because many families or groups of friends have their own traditions for holidays that make it both difficult and amusing for teams to guess. For example, if the holiday is Fourth of July, the riddler could act out setting off fireworks. Also, if the family has a tradition of a barbecue or a camping trip on the Fourth of July, this could be acted out as an inside joke that will be fun for the team to guess.
Animals
Animals can provide a hysterical category for charades because many animals have unique walking, eating or life habits that are amusing to guess. For example, if the riddler is trying to portray an elephant,the could walk around using his arm as the elephant's trunk. He could also pretend to be part of a circus, as an elephant is one of the most commonly seen animals at a circus.