I'm taking CS50 via edX. Will I get to showcase my final project in the CS50 fair? Also, when is the fair held?
The CS50x "Fair" is an online website that showcases the video project submissions. There is no set time for it. Presumably your project video will be added at the end of the course.
You can see the current 'fair' which includes the projects done for the 2012/2013 run of CS50x here: http://expo.cs50.net
Usually, upon submitting any PSet, you get asked if CS50's staff could upload your work to their website (or something like that - I don't remember the exact wording). Thus, I would assume that once you submit your final project to them, you'll be asked if you would like to have it displayed on the CS50 Fair.