If you're a driving enthusiast of any sort, and you happen to be in northern Europe, you should really take an extra day to get yourself to the Nurburgring in central western Germany. I haven't had a chance to do it on a motorcycle, but I have driven it a couple of times in rent-a-cars, and it is AWESOME! Not only are you working through 70-some-odd curves over 21km (with the longest straight being only about 2.5km), both climbing and descending, but you're also traveling through a really picturesque wooded area.
I drove this in my pre-motorcycling days, and I gotta tell you, I gained immense respect for motorcyle riders as I was doing everything in my power to keep my rented BMW 320i from losing it around these corners and the bikers are passing me like I was standing still! Didn't ruin my fun, 'though. After each lap I was sweating and shaking - had to rest about 20 minutes in between each of my five laps.
'07 DL650 ABS
'04 Yamaha V-Star 650 Classic Silverado (gone)
'04 Yamaha TTR225
'03 BMW F650GS (wife's)
'92 Honda XR250L
'86 Honda VT500c (gone)