[C M Burns]

I think a well written interesting essay is more important that the topic. these guys read hundreds in a row. But as people have said you don't want to come across as a guy who will be more into gambling than school. A good angle might be to talk about how this "hobby" has sparked a broader interest in some more mainstream things like psychology or math that you may want to pursue in school. make it less "about" poker and more about things you have learned or gained interest in. admissions guys wouldn't be admissions guys if they didn't go for a little personal growth bs.

Examples and anecdotes usually read the best. maybe talk about a specific hand you played and how it got you to think about how people think or the math involved. also it may be better to say you play games with freinds or family rather than sneaking into casinos or even online. If it sounds like something your dad taught you rather than something you do instead of homework it will sound better.