I have a student who is in charge of Northwestern’s Undergraduate Economics Society and he is planning an event in the Spring.  They have some money and they want to organize an activity for their membership that will be fun and economics-oriented.  Think of this as an opportunity to design an experiment involving any number of students (up to hundreds of students), but it should be fun as well as educational.  I know that our readers will have some good ideas for them.  Please share them in the comments.