I thought that custom robo arena was a really good game, my other favorites include chrono trigger, FF, DQ, advance wars, Staffy, wario ware touched, and more.
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so here's what I got me: a mario kart red DS phat, EZ-flash (who knows what firmware, I update when I want a newer game, haven't had time in a while), some badass earbuds that make the bass louder, and a 2gb microSD