There are plenty of ways to share your books, both "wild releasing" and by "controlled releases".
It might be worthwhile you visiting the German forum:https://www.bookcrossing.com/---/14
The (Not-So-) Random Acts of BookCrossing Kindness forum has lots of interesting things is there including sweepstakes and giveaways::http://www.bookcrossing.com/---/10
The Wishlist Tag Game is a great way to give a book, and get a book.
There are a few of them, this is the European one:http://www.bookcrossing.com/---/489942
The game is played by 'Tagging' someone with a book on their Wishlist, and then you will in turn be Tagged with a book on your Wishlist.
Make sure you have the sort options set to "Flat - Latest First" so you can see who is next in line to be tagged.
Simply check their Wishlist, and if you have a book that features there, and are happy to pay the postage to send the book to them, tag away!
Here too are the links for the International Games:http://www.bookcrossing.com/---/464693http://www.bookcrossing.com/---/464746
You might also enjoy the Bookrings, Bookrays, and Bookboxes forum which exists to coordinate group book sharing amongst members.http://www.bookcrossing.com/---/20
Incase this is total info overload here is the link to the FAQ'shttp://www.bookcrossing.com/faqs
Welcome again and enjoy the site and all it offers.