Scribblenauts was quite popular on the DS, impressing the public and press alike with its unique brand of God-based puzzle solving (because he was the answer to almost all the puzzles). The original game apparently sold a little under two million copies and its sequel, Super Scribblenauts, managed to sell a little over a million since its release in 2010, but it's the iOS version that's been the one to watch.
Yesterday, it was announced that Scribblenauts Remix has sold over a million copies since its release in October last year, and shows no sign of dying down. To celebrate, the developers have released a Valentines update which is available right now and offers a "Valentines themed playground," in which to vent your frustration or joy at the holiday in general.
If you haven't bought Remix yet and want to aid in the push to two million, the game costs less than a dollar/pound and is available via iTunes.