As the App Store nears the alluring one billion download figure (and you thought a million was a big number, huh, Ashton Kutcher?) Apple?? taking a moment to plug its most popular downloads. Interestingly, of the top 20 paid-for apps, 14 were games, including Vivendi?? racing kart title Crash Bandicoot Nitro ($5.99), 3D puzzle, Enigmo ($3.99) and trusty favorite, Bejeweled 2 ($2.99.) Me? I??e been playing Drop7 ($2.99), which seems to have usurped Scrabble ($4.99) as my current iPhone game obsession of choice. Creators Area-Code (about whom I wrote this story a while back) describe it as ??etris meets Sudoku.?I describe it as “infuriatingly addictive.” Area-Code also just released Facebook Connect support for the game so that friends can compare scores, which is crushingly depressing as I had been blissfully unaware that such high scores were even possible. Anyway, what other games are people enjoying? What’s the best type of game for the mobile context? Why does an idea as simple as Drop7 encourage such OCD behavior? Tell me!