Hey Lucy,
There's a few people currently at Durham who didn't pick it, but believe me you'll be glad you're there now!
Music wise, we have open mic nights about every 3-4 weeks and also have various bands and stuff you can join (such as the Jazz Band, who performed a very entertaining Blues Brothers number near the end of term). Also, our Butler Live society gets live music from around the country and the best of Durham to play at Butler too (no big-hitters, more up and comers like the Marsicans and Michael Cassidy). There's also a music room that is free to book and practice in, along with instruments. (Being done up this year I think, joyous).
In terms of theatre, every term, the Society of Theatrical Arts at Butler (or STAB) put on a performance. A lot of the guys involved with this also take part in Durham Student Theatre which is by far the best way to hone your acting chops at Durham. My housemate is currently taking an original production to the Fringe, so you really get to immerse yourself fully in the experience.
General stuff about college: it's like a big community feel as all the accommodation is within spitting distance and the Bar is constantly in use, whether for the numerous charity events we put on, post formal entertainment or revision space. If you want more elucidation on these things, find our Facebook group (it's in the self-FAQs) and ask away!
Taha
Head Frep