WHAT ARE YOU DOING
Group gets in a line at the edge of the playing space. The first person enters the space and begins to pantomime a simple activity -- for example, brushing his teeth.
The second person runs on and says, "What are you doing?"
The first person may answer anything EXCEPT what he is actually doing. In our example, he might say, "I'm washing the car." He may NOT stop his pantomime until he answers the question.
The moment the second person hears the answer, she must begin immediately to pantomime the mentioned activity.
The first person goes to the end of the line and the third person runs on and says, "What are you doing?", etc. After a while, add to the original formula, "I'm ________." It can become, "I'm ________ with a ________." Eventually, it can become, "I'm ________ with a ________ while ________." (For example, "I'm painting the barn with a codfish while snorkeling." It doesn't have to make sense.) The second person must begin to act as soon as she hears even PART of the answer. (In the example, we should see her painting the barn even before she hears that she's using a codfish. When she hears about the snorkeling, she'll have to adjust.)
You can play this as a tournament if you want. Two people bounce the question back and forth until one of them "fouls" by repeating himself, stopping the action before answering the question, not starting the acting in time, or answering the truth. A new challenger steps in, and so on, until all but one person have been eliminated.