There's no more popular mobile game in all the land right now (if by all the land, you mean "the United States") than Six!The GramGames puzzler which is one part Tetris, one part Jenga, and one part it's own thing has captured the imagination of the casual crowd, leading to plenty and plenty of downloads.
It's simple enough that it doesn't need a ton of explanation. That's great for you, the player, yet something of a bummer for me, the explainer.
Does that mean we're done here? Perish the thought, friend. They haven't invented the mobile game yet about which I couldn't wax poetic in some (hopefully) helpful way, and when it comes to Six!that means two related questions: How can you rack up more stars faster, and what do you do with them once you have them?