http://ccmixter.org/
ccMixter is a community music site featuring remixes licensed under Creative Commons where you can listen to, sample, mash-up, or interact with music in whatever way you want.
Remixers If you’re into sampling, remixing and mash-ups grab the sample packs and a cappellas for download and you can upload your version back [...]
http://scratch.mit.edu/
Scratch is a new programming language that makes it easy to create your own interactive stories, animations, games, music, and art — and share your creations on the web.
Scratch is designed to help young people (ages 8 and up) develop 21st century learning skills. As they create and share Scratch projects, young people learn important [...]
http://www.co-ment.net/
Co-ment Features
Create, edit, share, collaborate and annotate text documents online.
Upload existing documents from local hard drive or create new ones.
Supported document formats: Open Office, Microsoft Word, Rich Text Format, Text docs (txt), etc.
Annotation: Highlight any text and comment on it.
Allow others to see and/or comment on the text.
Different sharing modes: Observer, Commentater, Moderator, Editor, Owner.
Document [...]
