Mnemosyne is actually very good

http://www.mnemosyne-proj.org/

it works on Win, Mac and Linux - written in Python

This should really be made into a web service. Where all the new card decks are shared for free. I think it could become a very powerful collaborative environment.

Hi! It has been by a few people including me. My site is here: http://flashcarddb.com

FlashcardDB allows a choice between two spaced repetition algorithms: Supermemo's SM-2 (like Anki, Mnemosyne) or the Leitner System. New card decks are shared for free.

Thanks for the rec! The first thing I'm going to be using Mnemosyne for is scheduling guitar practice. I often forget the number of songs and scales that I actually know. Eventually, they get dusty enough that I won't remember them at all. I'm hoping this will help me to retain much better.

I use this when learning a new subject. It's insanely good

Anki is a great spaced repetition tool; despite only using it for 20 minutes each day to remember the Japanese Kanji, it has resulted in me remembering a lot of characters (but English -> Kanji and vice versa).

If you're looking to memorise a lot of data, it's definitely worth a look (runs on Mac, Windows, and Linux).

I tried anki and while I liked it, I want to be interrupted while working on code/browsing to test/reinforce. Is there an app that does that?

I'm curious why you want to be interrupted while coding to test be tested. That kind of task switching would be horrible for me and is the reason why I have email turned off during coding sessions.

It would not work for involved things. My hypothesis is that if it's really quick recall, I'll be fine: I'm trying to reinforce the map from numbers to sounds (Harry Lorayne).

+1 for Anki. I loaded up a list of GRE vocabulary words in Anki, studied it for three months, and got a 1600. I probably spent two hours studying for other portions of the test. Takeaways: 1) SRS works; 2) the GRE is a joke :)