Giving away free beers at the Budweiser tent.
Barack actually yelled to the crowd, "Hey, everybody who's over 21, you gotta buy a beer!" Obama then bought 12 - two for himself, 10 for people in line behind him.
Obama's appearance was a poorly-kept secret, drawing thousands of fans, and creating security nightmares at the Hawkeye State's popular annual event.
But come on, a free beer from the Prez? Totally worth it.
Watch a couple of videos of his visit after the jump ...
