I assume you want to do the work of marketing/rebranding, not necessarily be the "executive" who does management and stuff (which is boring!).

You said you like music and culture. The good news is that a lot of music/cultural organizations need help with marketing. Even local bands need help. You could approach it like a free internship - try and find people locally that you can help. They'll appreciate the free help, you'll learn a TON, and build a network and portfolio along the way.