Why not just book flight tickets, rent a special car and basically drive around with a nice travel book to find all kinds of cool things? I had a blast driving around Germany with this book:
http://www.amazon.com/exec/obidos/t...002-2688192-9071207?v=glance&s=books&n=507846
Here are some links I found previously searching for interesting cars to rent:
http://www.turtlerent.de/
http://www.special-cars.de/
http://www.auto-online-mieten.de/
etc. etc.
You can find more with google searching for "vermietung" and the car of your choice.
I ended up renting an Alfa Romeo Spider from
http://www.europcar.de/ in Frankfurt railway station.
Driving around with the top down around the Rhine/Mosel valley area, Nürburgring and by night between the Frankfurt skyscrapers was a blast! Other cool places are the Neuschwanstein castle in the south, Eagles Nest/Berchtesgaden area, Rothenburg ob der Tauber (amazing old town!), bazillion nice small towns/roads, the alps in general and of course flooring it on the autobahn
. If you like beer, the Hofbräuhaus in Munich is really nice (well the beer is good anywhere.. heh) as is insteresting the BMW factory tour also in Munich (reserve in advance!).
While the autobahn is really exciting dont forget to take the small roads to see some Germany, lots of cool stuff to see. Really nice though to move around Germany on the autobahn when there is no Stau!