Blackmar-Diemer Gambit in my honest opinion is one of the most exciting gambit in chess ever! It gives you an agressive and sharp position. It is a pure gambit, white don't want to win back a pawn, but instead have something for that. Sometimes you will have the initiative, sometimes an attack, sometimes better coordination of the pieces, and sometime...well...nothing :D But don't worry, in order to achieve that, black will have to give up his material advantage (which is a pawn of course). Yes there are some secret lines in which black can even be more ambitious and try to keep his advantage and proove that our lovely gambit is unsound. About that I will write at the end of theoretical part. My adventure with that exciting opening started right after my come back in chess. As a small kid I played chess with big interest, winning prizes and tournaments. But life has written different scenario for me and I had to start working and then at the studies I lost interest of that game...