Thinkingwithportals.com

Thinking With Portals was a community based website focused on creating new maps for Portal and Portal 2. The site has been active since 2007. They offered a massive database of custom made Portal maps. They also promoted mapping contests regularly such as their Summer Mapping Initiative and Heavy-duty Super-mapping Super-contest. It went offline in December 2015 and currently redirects to a seemingly malicious website.

Contests

 * Summer Mapping Initiative
 * Heavy-duty Super-mapping Super-contest