SOOO-o-oeeyyy! While it might look strange spelled out, that word is the cornerstone of hog calling. Farmers call their hogs in this manner when it's feeding time, but these calls are also done recreationally in competitions across the country. Competitors are typically given 30 seconds to do whatever they'd like, and are often awarded more points based on how long they can hold certain calls. Creativity, costumes and props are often encouraged, making it quite the spectacle for everyone watching.
The following clip is taken from the Hog Calling Contest at the 2010 Illinois State Fair. As you can see, the participants manage to be silly and have fun while still demonstrating mastery over their craft.