Can I refuse to go to this crappy festival that is being held?
Don't you think it will be worth your time?
No, I think it's not worth the trouble.
You have no liking for a festival that will turn out to be bad, and that can be true. If you go to it then you will have no fun, and regret the time you wasted. You would be able to finish studying for your math exam instead of going to something exciting like the festival.
I don't like fun things.
I can understand your feelings. You don't have to go anywhere you don't want to go. If you are set against it, then you will just be more miserable forcing yourself to go.