But I do, so it is.
A calvinist arrives at Heaven's gates and sees that there are two queues going in. One is marked "predestined," and the other is marked "free will." Being a good calvinist he wanders over to the predestined line. After a few minutes an angel asks him, "why are you in this line?" He replies, "I chose it." The angel looks surprised, "well then, you should be in the free will line." So our calvinist, now slightly miffed, obediently wanders over to the free will line. Again, after a few minutes another angel asks him, "why are you in this line?" He sullenly replies, "Someone made me come here."
For a different type of chuckle about calvinism, try this piece from Christianity Today.