Codecademy is an interactive, online learning platform to learn programming. You might recognize them as the brains behind Code Year. The team at Codecademy recently launched a series of courses on a topic near and dear to the Mandrill team: using APIs. If you've never worked with an API before, the Codecademy team will take you through a series of lessons about APIs generally so you can get your bearings and then you'll dive right in to working with an API.
Without further ado: head over to Codecademy to get started with the Mandrill API.