I thought that this was a good site because it has a lot of pictures and graphs for those people who learn on a visual level. The animation is particularly useful because it let's you see how the activity is applied in real time.
I was surprised that for a website that uses animation there were no time lags and the load time was quick. The topics were organized in a neat manner as well.
Time spent reviewing site:
I spent twenty minutes looking at the different images.