You need to be familiar with the language and its data structures, some experience in package development and understanding of JSON goes a long way but is not necessary.
Roughly 3 hours of fun!
Probably not, you already know most of what will be taught.
June 20, afternoon 14:00-17:00 CEST
Please feel free to contact me via Twitter (direct messages are open to anyone) if you have any question; @jdatap