One “artifact” that I use regularly (at least three times a week) and really love is the Nike+ App and website.
I love it because through an object that I carry everywhere (my mobile phone) and the App I am able to record my running. The website/app allows me to compare my progress through time and “compete” with friends (weekly and monthly leaderboards). At the same time, it has a way of motivating through badges for different acomplishments. I think it is a good example of gamification.
Coursera course Design: Creation of Artifacts in Society