Duolingo
Other than an old pen-and-paper game I created and played to get out of a slump in work several years ago, Duolingo is the first program I’ve really used that uses game mechanics for skill acquisition.
It’s basically a learning module for languages - in my case, Spanish. It has discrete chunks of info, and as you “play” you learn how to use the language. Each positive answer is followed by positive sound. Incorrect answers mean losing a heart (like Supermario!). If you lose all three hearts, you have to start the level again. You gain points and gain levels, and can practice out your skills later on by helping to translate portions of the internet. It also has a community aspect in that you can see how far your friends have progressed and leaderboards.
So far I really like it, and it’s definitely more engaging than any other language learning software I’ve used.
I chose this as my first program because 1) It’s a skill that everyone says they want to work on 2) I personally do need it and 3) it’s a very well developed program.
I’m currently Level 5 in Spanish - you can check out my progress here:
http://www.duolingo.com/#/BijuHero