One of our lecturers used to ask the audience a question, but rather than ask if anybody knew the answer there was a paper airplane that he would throw into the class. The rule was whoever it landed closest to got asked a question. When he wanted to ask another question that person got to throw the paper airplane to see who would have to answer that one.

It hadn't landed near me until the last lecture and the lecturer said "Is this the first time that it's landed near you?". I replied with "Yes", to which he responded with "Damn, that was I question I asked! Throw the plane"