One of the main highlights of getting married, after the whole marriage thing of course, is the big first dance. Everyone waits for the new bride and groom to perform either a slow, romantic dance, or pull off some other crazy shtick.
The Vanhorns knew they wanted to really shock their guest at their wedding, so they practiced a full swing dance performance from the times of big band music. Having great taste, they chose Sing, Sing, Sing by Benny Goodman.