The game primarily comprises a series of puzzles that must be solved by teleporting the player's character and simple objects using "the handheld portal device", a device that can create inter-spatial portals between two flat planes. The player-character, Chell, is challenged by an artificial intelligence named GLaDOS (Genetic Lifeform and Disk Operating System) to complete each puzzle in the Aperture Science Enrichment Center using the portal gun with the promise of receiving cake when all the puzzles are completed.
(No, it wasn't the cake-thing that made me curious. Nope.)
Actually it was my brother who bought The Orange Box and unlike him, I was more interested in Portal than the other two games included. *grins*
And just a few days ago I found on Quiet Earth a Live Action Short Film by Dan Trachtenberg.
From there it wasn't far to another awesome short film.
Now all that's missing is an actual movie about it... xD