Suppose that many students in New York public schools own cell phones.  Summon all your powers of imagination for this one.

Now suppose that instead of banning phones, the city gives one to every student in the system – a phone called the Million.

During school hours the phone can’t make calls or send texts, but it can be used to do research online and interact with materials teachers distribute electronically.  As students do homework and get good grades, they’ll receive an allowance of minutes to call their friends after school.

(via Freakonomics)