Chompers is one of the best things I've yet heard of the the Amazon Echo. It's a daily (ish) podcast that lasts less than 5 minutes, and is designed to encourage 3-7 year olds to brush their teeth for 3 minutes or so.
It's perfect for the Alexa because kids or adults just need to say "Alexa - start Chompers" for it to start; no one wants to be touching buttons or their phone screen when they're about to brush their teeth.
More here, inc some episodes to listen to.