I'll throw my 6 cents in (thanks to recent pinflation) I'll say while I'm not a Nascar fan, one weekend a neighbor had tickets and offered to take me and my boys along with him, WHOA it was amazing! I was awestruck and had a fantastic time.
I'd long been an Indy fan and would jump at the chance to see one of their races. They brought the circuit here to Houston a while back and it just never worked out that I could atten, but the the OPs comments about the CART/ Indy issues and splitting up, that is about when I quit watching on TV. I'd still go see a race though.