Creativity Pool Save
A global pool of innovation and new ideas. People can browse the database and search for creative inspiration, or donate their unused creativity and be rewarded.
http://www.creativitypool.com   

Global Ideas Bank Save
An International Suggestion Box for socially innovative non-technological ideas and projects, with £1,000 UK sterling awards annually for the best ideas or projects submitted.
http://www.globalideasbank.org/   

Halfbakery Save
A communal database of original, fictitious inventions, edited by its users and spanning many topics.
http://www.halfbakery.com   

Idea A Day Save
A new idea every day.
http://www.idea-a-day.com/   

Thinkcycle Save
Idea open source forum seeks to create a culture of open source design innovation.
http://www.thinkcycle.org/home   

Forum - Usenet alt.inventors

Help build the largest human-edited directory of the web
Suggest a site | Open Directory Project | Become an editor