According to the team's press release:
"Some of the most famous dance halls in the country include Radio City Music Hall in New York, the Fox Theater in Detroit and now the list includes a restroom at the Minneapolis/St. Paul Airport. With so much fanfare around dancing, the St. Paul Saints will honor "tappers" during National Tap Dance Day.The Saints' principal owner, Mike Veeck (son of Bill), is no stranger to unique promotions. My favourite was "Vasectomy Night" -- which ended up being cancelled -- or snipped from the schedule, if you prefer.
"... The design is a bathroom stall, with a foot that peaks out of the bottom and "taps" up and down. The day coincides with National Tap Dance Day.
"While many people tap their foot because they are impatient, others may do it because they are nervous. It doesn't matter if your tapping style is done with a "wide stance" or is used as some sort of code, the Saints are asking all fans to tap to their heart's content on May 25."
(thanks to uggabugga)