There's a yearly 100 hole tournament at Hamburg's Falkenstein, one of the best courses in Germany (Harry Colt). I haven't played in this event, but know some who have and they all wholeheartedly recommend it. The course is obviously reserved for the tournament and there is always a large crowd in the evening to welcome those, who actually made it. They are in their 45th year or so, so this one of the oldest tournaments anyone can play (well, handicap 12 or so needed).
It takes place on the longest day of the year (June). You start at 4:20 AM and play the first three rounds continously. At about 11:00 AM there is a short break and then you head off for rounds 4 and 5. That is the point where most participants lose track of the time and things get ugly. Most will return to the clubhouse at some point and a few will go out yet again and complete the 100 holes at around 9-10 PM. It'll cost you something like 10$ per round - you'll never play one of the world's top courses cheaper than that.
Ulrich