Do you want to make "khan academy" style videos? Khan academy style is "write on screen" and make a screencast of it.
How can I create web based exercise or quizzes for my students? This question is very common among the teachers who want to incorporate technology in teaching.
I was also seeking answers to this question when I was new in the educational technology arena. I found a very useful software that I use frequently and recommend to others also.
In order to use this tool you don't need to know any programming language. The exercises build using this tool are compatible with W3C standards. This tool is freeware but not an open source.