This one may violate the do not try to use SRS unless you understand it principle. But for those who understand mathematics, this book consists mostly of definitions, which are compact enough to use an anki deck for.
http://www.amazon.com/Mathematics-Web-Linked-Dictionary-Collins/dp/0060851791
Spaced repetition is a powerful learning tactic, and Anki is a good tool for it. There are some LW-relevant Anki decks here. But I wish there were more.
Which sets of knowledge are (1) likely useful to LWers, and (2) straightforward to encode into Anki decks without needing to be familiar with that field?
Some examples:
Which other sets of knowledge would you like to see Ankified? Please link to the actual knowledge set you'd like to see encoded.