Laura Dubuk is an artist and designer employed at Valve, where her most recent public work was her contribution to the studio's terrific Meet the Pyro trailer.
She's also worked on games like Portal 2, and in this gallery you'll see a collection of some of her best stuff, both from personal projects and from Valve games.
Note that you may have seen that top pic before, especially if you've been to Michael Fahey's house.
If you like what you see, you can check out more of Laura's work at her personal site.
To see the larger pics in all their glory (or so you can save them as wallpaper), right-click on them below and select "open in new tab".