Whilst at my last school I redid some of my introduction to python videos and we used www.repli.it to teach the students, so we may as well share them here too. Nice easy way in for 4 lessons, and as an assessment we asked them to  research the modulo function in python and then do the classic Fizz Buzz exercise as an assessment.

Lesson 1 - Basic chatbot

Lesson 2 - Making a Calculator

Lesson 3 - Hi Lo game

Lesson 4 - Pythagoras