This introductory workshop took Hack Reactor students and guests through building a Polymer Element. Polymer is "a library that uses the latest web technologies to let you create custom HTML elements" The idea is to build a variety of familiar things, from buttons to complete applications. Then you can reuse those elements you build--even on mobile.
It's not too late -- see Dave Edelhart's presentation from Fri! Dave is a Developer Experience Engineer at Leap Motion and was onsite at Hack Reactor with 30+ Leap Motions for students and attendees. He presented "Intro to Leap Motion w/Three.js" followed by a few hours of hands on coding.