This is one of my favorite site for puzzles. There is one puzzle every day you can solve there online and compare your timings with the best in the world. Based upon your daily puzzle solved, you will ranked to create your world puzzle ranking.
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There is weekly contest on the site where you can win prizes and with that prize money buy the croco magazines.
Check it out Croco Puzzles here.
Instructions are in German but one can use Google Translate to translate in the language you want.