I’ve been working on a pretty cool project based off of pulltabs (essentially private side scratch cards) and integrating them with slot machine mechanics.  The tabs have a code that allow you to play the slot machine.  The more you win on the tab, the more you win on the slot.  Of course, the slot machines are for an entertainment purpose only (it’s just an abstraction of the pulltab value), but it can be fun to make casino style games in a mobile format.