OGame - OGame is an addictive, Massively Multiplayer Online, Real-time Strategy, Space-war, and Money Management Browser-based video game develop by Gameforge AG.
Startup School - How to start a startup, by Y Combinator
EVE Online - Player-created empires, player-driven markets, and endless ways to embark on your personal sci-fi adventure.
YC World - Explore Y Combinator companies by country
Galaxy on Fire - Galaxy on Fire is a space combat and trading simulation.
Y Combinator Companies - Interactive list of all 1000+ YC companies