Zillow - Is that home for sale? What is it worth? Where can I find foreclosures? Stop wondering!
Space Engine - Space Engine is a realistic virtual Universe you can explore on your computer.
Trulia - Trulia’s top-rated real estate app helps you find the perfect home, wherever you are.
Celestia - Real-time 3D visualization of space
LoopNet - LoopNet is an online commercial real estate marketplace that connects buyers, tenants, and investors.
Stellarium - Stellarium is a free open source planetarium for your computer.