Schönes-Wochenende-Ticket

Lonely Planet says:
"The so-called Nice-Weekend-Ticket is Europe's finest rail deal. It allows you and up to four accompanying passengers to travel anywhere in Germany on one day from midnight Saturday or Sunday until 3 am the next day for just €30. The catch is that you have to use local trains and not IC, ICE, or IR trains. Munich-Berlin takes 11 to 12 hours, with five to eight changes of train- not a bad deal for the price. Bring a good book and pack a beer in your lunchbox."

We packed a bottle of wine in our lunchbox and did Freiburg-Dresden in 13 hours, with 6 changes of train. Booyah! That same ticket would cost 162 euros for the two of us on a weekday.