Ludum Dare has been so much fun over the years. We've been doing it for 2 years now, and have had mixed success :-)
http://www.ludumdare.com/compo/2013/12/13/playcanvas-is-in/
But we've created some awesome little games (and some less awesome ones) but always learned and pushed our platform forward that bit.
2yrs ago, http://apps.playcanvas.com/dave/alone/latest
1.5yr ago, http://apps.playcanvas.com/dave/tiny_world/latest