I make ~$2,000 a month with an iPad game for cats. My co-founder and I were working on a "more serious" game and it was taking a long time. We needed a quick win, so I agreed to do it if we spent less than 4 weeks on it. We completed the game from idea to app store in 3.5 weeks and it is now, by far, our most popular game. * face palm * EDIT: We split the revenue 50/50, so the revenue (after apple's cut) on this game…
Wait a second, the iPad app is free. Are you making money from cats clicking on ads ? If so, I salute you.
But the fine print on http://www.ipadgameforcats.com/ says that one level/theme is free and another is $1.99 as an in-app purchase.