Looking for an engrossing game for a long trip.

I'm going on vacation in a couple of days and our flight is over 10 hours. I can't sleep to save myself on a plane, so I'm looking for that engrossing game where I can just feel the hours turn into minutes. I would love an RPG with a great story, if there is one out there. Something similar to the Tales games or even Dragon Age (I've played Dungeon Hunter and that wasn't bad). Something decently long as I want it to last at least 15 hours so I have it for both plane durations. I don't want a pickup and play game as I have tons of them. Has to be for iPad.

If you have any suggestions, I'd greatly appreciate them.

Thanks.

Civilization is a great one, and the MtG game from WotC just dropped... Those will keep you busy for a long, long time.musicalmac

Edit:- didn't see the IPAd part but GTA chinatown wars has a specifc Ipad port anyway and it still worth picking up for the story missions alone.

Minecraft Pocket Edition isn't as good as the original, but still might be fun for a long trip. It eats away at battery life though.

Samurai Bloodshow is a decent strategy tower-defense game. It employs a card-drawing system. It is kind of challenging though.

Plants Vs. Zombies is still probably one of the funnest games on the iOS, and is a great value.

Most of the other games I know of run off of 'energy' in-game, and you could only play them in short bursts every few hours.

EDIT: Oh yeah, Army of Darkness Defense is great too.