Wikipedia
MadHatters
The MadHatters is a collegiate a cappella group on the University of Wisconsin-Madison campus. Created in 1997, the MadHatters are the first established a cappella group on the UW-Madison campus. The MadHatters have grown significantly in popularity in the a cappella community, having released several albums and receiving several awards. The MadHatters are notable for being featured on two Best of Collegiate A Cappella (BOCA) compilation albums as well as hosting the International Championship of Collegiate A Cappella. The MadHatters traditionally have between 9-12 vocalists and one vocal percussionist.