http://getmpoints.com/
http://www.sessionm.com/
Its basically an achievements system fed by advertisments.
They don't put ads in your game, they give your users rewards for looking at ads.
It's useful as it makes it a lot easier to get daily views, plus it allows you to add your own achievements.
Anybody whos used Crackle will probably have seen it.
They have an sdk for Ios, Android, as well as Html5.
Good idea for a plug, no?