If there's two things in this world I love enough to offer my firstborn, that would be food and then music. In that order.
Music attracts a subset of people who are oftentimes very right-brained; the type of folks who suck at math and other left-brained activities. And unfortunately, a large part of learning music theory (especially rhythm) is mathematical.
Even worse, now that the majority of elementary and middle schools in the nation are cutting out music programs, kids are growing up with no clue about rhythm.
Sure, they've been exposed to it just by hearing music, but they don't know how to think about it. Have no fear, because Ledger Note is to the rescue. Explaining the lengths of notes is a nightmare, and doubly so when you try to associate the lengths with the actual notes on paper!
The problem is solved with The Hungry Man's Guide to Musical Rhythm:
And that's just beginner level! Try this one on for size:
Biscuit Ketchup, Ketchup to Biscuit
Bam, now you're a beat-boxing maniac! And now I'm hungry :(