Yes you can watch the lecture videos when you want. Check out the EDx demo. There is lots of courses on EDx and Coursera from top universities ( classes are free, but certificates of completion usually cost money, though honor code certificates are usually free). I'm completing an intro to computational thinking and python course this week (6.00.1x MITx) and I'm very impressed. It was challenging and demanding at times, but lots of fun and most importantly I learned a lot. The second part of the course starts in October (6.00.2x). If you are looking for "go at your own pace" classes I highly recommend checking out MIT OCW, they put all their courses online for free (lecture videos and course materials).
Udacity also has pace yourself courses created by Google and Stanford types. Basic versions of the courses are free but certificates cost money.
https://www.edx.org/how-it-works
http://ocw.mit.edu/index.htm
https://www.coursera.org/about/
https://www.udacity.com/course-experience
