As a gen ed instructor, I have to find ways of keeping the topics a bit more lively and I always think that competition is a good way to do this. I bring candy in for the students (raisins, too) and toss a piece across the room for a correct answer, a good try or even just because they haven't had a right answer yet! I also do a surprise "Bonus Point of the Day"--for anything from being the first student in class,helping out a classmate, being prepared or even making me laugh out loud. The students respond since they never know what it will be that day OR how many bonus points will be given out.