Student task: Take a UPC code off of any product from home. Write down the UPC code on a piece of paper with your name. Leave a question mark in place of one of the digits. Do not include the name of the product. Pass the paper to a friend.
Friend check: Find the missing digit in the UPC code you received. Now look that number up on Google. If you got the number correct, you will find whatever product your friend had in mind. If you don't find anything, go back to the drawing board.
Student task: Work in groups to create your own calculus riddle. For example, "What do you call a finely dressed calculus student?" "A tangentleman!" of course. You will encode the punch line to your riddle by transforming each letter into a number using the code A = 1, B = 2, C = 3, D = 4, …, Z = 26. Then you will create a definite integration problem with that number as its answer. For example $2\int_0^1 x dx=1$, which becomes ‘A’.
Friends check: Decode your friends' riddle by evaluating the definite integrals. If you do this correctly, you will end up with a punny answer to the riddle.