Course link: https://www.coursera.org/course/softwaresec
This course is really interesting, especially the course projects. I have accomplished two projects out of three.
Project 1: Exploiting Buffer Overflows in C
Project 2: Exploiting Web Application Vulnerabilities in BadStore.net
The challenging projects are practical exercises for me to find the vulnerabilities of a program or a web service. Meanwhile, to find the answer of assignments, I learn several techniques of attack. Although I spend much time on doing these projects, I still enjoy in these puzzles.