So this guy Steve Thomas (and that may even be his real name) did some fantastic - no, wait, mind-blowing designs for interstellar travel based off the look of those old WPA national park posters.

For example:

You can see and purchase all of them in his Zazzle shop.

I am seriously contemplating just how many I can afford to put up in my place before I look like a world-class sci-fi dork.