If you happen to be an old-school type computer RPG player, you could do a lot worse than waste some time with Legend of Grimrock. It's a Dungeon Master type 3D dungeon crawler with some pretty good gameplay, especially on an iPad. All the traditional elements are there - real-time movement and combat with environmental factors, party skill tradeoffs, resource management, spell discovery, equipment juggling, and the like. Plus more puzzles, secrets, and little nooks and crannies to discover than you can shake a stick at.
An Ogre. My current party are Ogre-slaying machines. They've killed hundreds of them. OK, OK... scores. Dozens. Well, at least a dozen, surely. No? How about... three? Yeah. Now that you mention it, it might have been three. Forgive me if my memory is a little fuzzy. It's probably because those HUGE FREAKING OGRES KEPT HITTING ME OVER THE HEAD WITH THOSE STUPID BIG HAMMERS. Ya think?
I suspect that it also has high replayability, as well. I am currently a little over halfway through the game's thirteen levels, and already planning how I am going to put together my party for my next run through.