I think your parents should let you go, I mean, you only live once, and it's only one day of school. But still, if they say you can't go, then you should listen.

Still, it can't hurt to reason with them. If they are worried that you'll be tired, maybe offer to go to sleep early the night before and take a nap between school and the show. Show that you understand their concern, and try to work out a solution that everyone can agree upon.

What concerns me most is that they think you need to keep up your grades. What's going on here? Are you having trouble with your grades?

On a side note, Cradle of Filth definitely sounds like my type of band. I mean, I don't really like filth, and a cradle full of filth doesn't sound like anything I'd be interested in. But I love that sort of "black metal" music. I do agree that it is an acquired taste. In fact, watching music videos of this band on YouTube is confirming that I like this band. Maybe I should purchase one of their CDs...