I find it hard to take a viral app and make any kind of significant revenue in a short time, no example comes to mind. But if this was the case I would suggest

I find it hard to take a viral app and make any kind of significant revenue in a short time, no example comes to mind. But if this was the case I would suggest, possibly a compliment iphone app that costs like 99 cents to capture paying customers of the apple market. This market seems to pay for things like this , example fart app.