We did this several years ago and it was a blast! You split up your attendees into groups and make them stand in a line. Then you give each team a spoon tied to a really long string, and each player has to run the spoon either up or down their t-shirt and pass it to the next person. The first person to get the spoon all the way down the line wins! I know it sounds silly, but that's kind of the point, right?
The video below wasn't our event, but you can see roughly how it's done. They went more extreme and made the people go through tops and bottoms, which may be a bit too much! (Skip to minute 1:44)