Hey folks, we (Code School) made this with GitHub in 2012. It keeps being plopped on HN year after year which is great but it would be nice if everybody realized that we did this as an introduction to Git — not as an end-all-be-all.
We make interactive courses, and we have an entire Git Path where we get into Git a lore more deeply. Try Git was build as a free resource at a time where a lot of people were very Git shy. It's been mostly left alone since then. I'd love for us to revise it, but sadly we haven't had the time since.