What's a good iOS game to kill some time without needing internet, maybe something with music?

Look, I spend a lot of time driving between job sites, and sometimes the signal is just plain awful. I need something that doesn't eat up my data. Music Tiles 2 is actually pretty good. It's a piano game, so it's not just mindless tapping – gotta pay attention. I was surprised to find some pop songs mixed in with the classical stuff, which keeps it interesting. Plus, it doesn't need internet, which is a huge win for me. Beats staring out the window for hours. For a free game, it's worth every penny, especially when it keeps me from going stir-crazy. Bottom line: it's a solid time-killer for those dead zones.