There are, at least, two groups by this name. Ballyhoo (without the exclamation mark!) is a South African group who had a huge hit in 1980 in their homeland with their single 'Man On The Moon'. This South African group is still going strong. The other group with the same name (but with the exclamation mark!) is from Maryland, USA, a modern rock/reggae party band, active since 2006.
These are photos from concerts where Ballyhoo! played, so they may be of other bands that played the concert as well.
Vans Warped Tour 2012 Aug 5, 2012 Portland, Oregon, United States Uploaded by Edwin
Vans Warped Tour 2012 Aug 5, 2012 Portland, Oregon, United States Uploaded by Nikole Lane
Warped Tour Jul 29, 2012 St. Petersburg, Florida, United States Uploaded by Largobob