Integrated Open Source Solutions
TinyMCE
This site uses the Open Source editor TinyMCE. A special thanks to the folks who have done a truly wonderful job creating this component.
EPPlus
This open source project has created a fantastic server-side Excel document creation component
http://epplus.codeplex.com/
JQuery
http://www.jquery.com
JQuery UI
https://jqueryui.com/
Chiron: SilverLight Dynamic Languages SDK
http://www.codeplex.com/sdlsdk/Wiki/View.aspx?title=Chiron