It's been a long time since I craved a computer program, but now I want Space Engine so much that I'm ready to buy a PC just to be able to immerse myself in it. Developed by Vladimir Romanyuk, Space Engine is a complete sandbox simulation of the Universe with mind-blowing graphics. Check this out:
From the description:
SpaceEngine: a free space simulation program that lets you explore the universe in three dimensions, from planet Earth to the most distant galaxies. Areas of the known universe are represented using actual astronomical data, while regions uncharted by astronomy are generated procedurally. Millions of galaxies, trillions of stars, countless planets - all available for exploration. You can land any planet, moon or asteroid and watch alien landscapes and celestial phenomena. You can even pilot starships and atmospheric shuttles.
It looks amazing. You can download it here if you have a PC with Windows XP or Windows 7.
Note to Mark Zuckerberg: Please buy hire the guy and include it with every Oculus Rift.