Highborn is an interesting little App Store title. It won't be for everyone -- it's a turn-based strategy game that has a pretty steep learning curve, and while the actual game itself is pretty casual as games like this go, players unfamiliar with of moving troops around could find it confusing. But those interested in the genre (the gameplay actually reminded me a lot of Nintendo's Advance Wars series) will find it a fun distraction.
You control troops and heroes on a tesselated board, and can pit various units against each other in battle. The story is silly and fun, and the emphasis is on simple advantages and odds rather than hardcore troop placement and balance.
It's not the only game of its kind on the App Store (Battle for Wesnoth is another example for a bit more money), but Highborn is a fun and original title that combines the basics of turn-based tactical strategy with a fun fantasy story and a portable package. It's on an introductory sale right now for US$2.99.