Well, here's another recommendation. Gamble Fish feels like a shounen ecchi version of Liar Game. Basically, a guy enters a private high school for rich elites, and starts challenging people to gambling bets. Each time they bet, they have to double the amount. He starts with 100 yen, and promises to convert it to 10 billion within a month. One by one, the elites of the school start to challenge him in various ways, from a bloody card game with the school's top magician, to a billiards game against the world junior champion, and more. But what is his motive for doing such dangerous bets? And why is he deliberately antagonising the rich and powerful?
Artwork is good, and storytelling is quite interesting. Most of the challengers turn out to be beautiful women, so there's some element of harem and fanservice involved, but really, it's the psychological warfare component that shines. And there's a really interesting Hiruma-like villain (Eyeshield 21) working behind the scenes. About the only unbelievable thing is the middle school setting... but frankly, that's hardly noticeable after a while. Scans are being done by OMFGG scans, and you can also read it on OneManga or MangaFox.