Via Raymond Chen, on Monday the Nashville Sounds, Milwaukee's farm team, turned a triple play against the Omaha Storm Chasers:
For those who don't know baseball's rules, a few things happened. First, a ball is "caught" (for an out) if the fielder making the catch gains full control over the ball before it touches the ground or another player, even if it touches a part of his own body—or his cap, as happened here. In the video above, this put the batter out.
Second, if a fielder catches a fly ball, all runners have to return to their last safe base before they can advance; this is called "tagging up." In this case, the runners started on first and second, and had advanced past second and third, respectively. The runner seen touching second base actually needed to make it back to first. So the fielder touching second put the next runner out, which is why the runner you see at second tried desperately to get to first again. He didn't make it; the first baseman forced him out.
It may have been an inelegant play, but hey, it ended the inning in 15 seconds.