Y Combinator Companies - Interactive list of all 1000+ YC companies
Mixergy - The YC Stories - How YC companies - Airbnb, Dropbox and more - Got Started
Apply to YC (Y Combinator) - Curated collection of resources for founders applying to YC.
Vibe Boost - An interactive digital museum of video-based art.
Startup School - How to start a startup, by Y Combinator
Endangered Sounds Museum - Nostalgic sounds from the past