[soccerdave]

Here are a bunch making anywhere from $50k per day to a whole lot more. You may need to be Facebook logged in to view them.

https://www.facebook.com/games/query/top-grossing/

Edit: Also, I believe Kongregate has a whole ton of games with In-App Purchases. I don't have any experience publishing on there but I do have experience on Facebook.

[benologist]

Facebook games are also declining, from Zynga at their peak to collectively less revenue than Candy Crush Saga on iOS.

http://www.businessinsider.com/facebook-payments-revenue-dec...

[soccerdave]

While it has declined, it is still almost a billion dollar industry on its own just on Facebook. You asked for "examples of games making heaps of money" and I included links to a bunch of them.