The next "Dream Rides" event is on this Sat 16th at Brooklands in Surrey (UK) for anyone who's interested. It'll run pretty much all day.
This is thing run by the Sporting Bears Motor Club - you turn up & pay some cash & get taken around a temporary circuit in a supercar/classic car/Rally car (driven by the owner, not you!) - whatever you select from what's there - Vipers, Ferraris, Porches, Lambos, Jags etc etc.
All proceeds go to the Rainbow Trust for very sick kids