During summer time Santa Teresa and nearby towns are very animated and organize festivals, concerts, live music, folk dances, shows and so on...
Here are some links to discover them:
http://www.santateresagalluraturismo.com/en/events
http://www.gallurabuskers.it/
https://www.musicasullebocche.it/
https://it-it.facebook.com/controevento/