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.
Misterwives / Ballyhoo! / Rubblebucket / Beach Slang Jul 23, 2017 Philadelphia, Pennsylvania, United States Uploaded by Rachael Eileen
Anti-Flag / Reel Big Fish / Pkew Pkew Pkew / Ballyhoo! Feb 16, 2017 Los Angeles, California, United States Uploaded by Felix Joel Garcia
Reel Big Fish / Anti Flag / Ballyhoo! / Direct Hit! Jan 8, 2017 Minneapolis, Minnesota, United States Uploaded by Twin Cities Media.Net