I use poker chips to award class participation. 3-4 different colors of chips, each worth a different point value, are awarded for different types of participation. Example: white chips = 1 point and are awarded for asking a question, green chips = 2 pts and are awarded for answering a question, blue chips = 3 points and are awarded for further explanation of an answer, red chips = 4 points for finding a practical application of the content. The students get really involved in discussion because it's a competition and the one with the most points at the end of the class gets a prize!