Time sink champions Nimblebit have a lot to celebrate -- their award winning mobile game Tiny Tower has just hit 10 million downloads. Of course, the game is free, but through micro-transactions, players can buy "Tower Bux" that allow them to speed up their progress.
Like most Freemium games, Tiny Tower banks on the fact that you'll become addicted at a higher rate than you're willing to wait for normal progress. Fortunately for us, Tiny Tower is actually a pretty solid game that can be an extremely fun way to pass the time.
Best of luck to the developers of Tiny Tower, who seem to have trouble with people emulating their success!