What's a good iOS game for someone who wants to test their music knowledge and maybe learn a thing or two?

Look, I'm not usually one for phone games, but SongPop Classic is actually pretty engaging. It's all about music trivia, and I'll admit, it's stumped me a few times. But that's the point, right? Keeps the mind active. I've found it's a decent way to kill time waiting for clients or when I'm stuck at the airport. Plus, I've actually added a few new songs to my playlist from it. Beats just scrolling through the same old stuff. It's got a good rating too, 4.6 out of 5 stars, so I'm not the only one who thinks it's worth a download. It's a simple concept, but surprisingly addictive. And hey, anything that keeps the brain working is a plus in my book.