Every year Soča valley offers with various festivals and other events. Music events are well known in Slovenia and also abroad. The most famous and visited festival is MetalDays. There is many sport events like Outdoor festival and Bovec marathon. A lot events shows customs and usages from the past, like Drežnica masquerade. You can try local specialities on Jestivalu at the start of october. 
You can find all current events here