If you biff it and you're lucky, your insurance MAY cover it, depending on the event type and the details in your insurance policy. If they do cover you, you can expect high premiums if they don't drop you entirely.
I have heard of people wrecking at the track and having it towed off to some remote location and claiming it was wrecked on a public road. As someone else pointed out, this is rather illegal (insurance fraud), and immoral.
There are supplemental insurance policies available, but I think for cars in our price range, you can expect to drop +/- $200 per event, but it has been a while since I checked (forget where..try google).
Most people just say 'Don't drive beyond your abilities and you'll be fine.' And that's true for the most part..but doesn't account for other people's jackassery, mechanical failures, etc.
Just remember the saying, "Don't take anything to the track that you can't afford to leave there." But also keep in mind, most people are just fine. Keep your head on straight, don't drive beyond your abilities, and keep an eye on others around you, and there's a 99.9% chance you'll be just fine too.