I always dreamed of having either a go-cart track or a mini-golf course of my own. I'd go for it. Don't forget that if it's a nice track there are other uses. If you have kids, they can ride bikes around it. It would be nice for walking around on (excerises is a must, especially for gamers!). You could also do RC-racing on it. It'd make a nice runway for remote-controlled aircraft too. I'm sure there tons of other creative uses for it.

I've seen folks on HDTV make mini-golf courses, putting greens, ect in their yards (sometimes front yards!). I don't think any of them regretted it