Moot is the better way to add comments and discussions to your page.
This in-browser Markdown editor can do pretty much. It's also not so hard to be integrated with other sources such as Google Drive or other platforms.
OpenFL :: Create high-performance Windows, Mac, Linux, iOS, Android, BlackBerry, webOS, Flash and HTML5 games and applications
They do a lot of good things related to learning and culture/media access.
Open books! A great initiative for the future of a book.
Run-time contracts implementation for CoffeeScript. You can define your own types and do many unimaginable assertions with simple code.
Faker is a little useful PHP library that generates fake data in a lot of useful formats.
Dischan is a group of people making visual novels, they are primarily known for their Disfunctional Systems game. #visualnovel
Flashcards? Google Spreadsheets? It's an all-inclusive. It could be a great tool for anyone learning new languages. #language #learning
A calendar that works under Wordpress and looks mighty fine. I don't know if you can add permissions for other site users to add their own events, but if so, it would work like a charm. #calendar #wordpress