FlowMapp - FlowMapp is a UX planning tool for creating visual sitemaps and user flow.
Google Open Source - All of Googles open source projects under a single umbrella
DYNO Mapper - Create Sitemaps with the DYNO Mapper Visual Sitemap Generator.
LaunchKit - Open Source - A popular suite of developer tools, now 100% open source.
Octopus.do - Build your website structure in real-time and rapidly share it to collaborate with your team or clients. Start prototyping websites or apps instantly.
Open Source @IFTTT - A collection of IFTTT OSS projects.