I'm a Clojure dev so I really like fast edit-compile cycles. Note, Ansible will happily take in JSON, so you can take your favorite language and write all the playbooks in that language. Just generate the playbooks on the fly (ie. genearte JSON not yaml) and shell out to ansible to run it. So you have all the features of ansible available but can arbitrarily build up your playbooks in your favorite language.
I'm a big fan of spaced repetition. From a mathematical standpoint it's also a very interesting question: You have your forgetting curve and which gives you the probability that you still remember the association. I think there is still some rooms for improvements around there. For instance, I'm not sure if the big plays in the area adjust the forgetting curve for each individual user after they have enough data points.
Shameless plug:
I actually just developed a new spaced repetition platform the last few years. I'm not official launched but it's online and works. If anybody is interested in taking part of the beta testing, email is in my profile.