And in the, "if you have to ask..." category, we have this 1962 Alfa Giulietta Sprint Zagato. I actually saw one of these a very long time ago at an owners club meet in Eureka Springs, Arkansas. They're amazingly small cars, with a really neat, blatty exhaust note. The owner had restored it himself, and said it was like driving around inside a drum. But a fun drum! I had no idea the things were so valuable. Then again, that was right around 20 years ago, so this may be a case of "when appreciation attacks!"
Update: Don't miss this even pricier TZ-1, the follow-on to the Sprint Zagato featured above. Vintage race cars, FTW!