Predela is the saddle between two mountains - Rila to the north and Pirin to the south. Every two years there is a folk music festival 'Pirin Pee' (meaning Pirin Sings) that takes place on the meadow in Predela.
The first issue of the festival was in 1962. The next one will be in 2008.
Since, coming probably from Sofia or returning to Sofia, you will anyhow pass Blagoevgrad by bus. You can, waiting for the bus to sofia/Bansko, explore this town then anyway. The city is not that historic as Bansko, but it has a rather open athmosphere, since its an international University town. So, it has a lot of nightclubs and pubs and some interesting cultural sights, such as the History museum (exposing items of archeological interest, military history and natural history) The town has also some renovated Bulgarian national revival period homes, art galleries, a park (were you have a good view over the town) and a botanical garden. The cities main interest is however, in my opinion, the athmosphere and the student life.