The classic striped wall shown in the two photos above is made from...get ready...masking tape. The color of the tape works well with white and the look is much more subtle, sophisticated and intentional than you would expect from a repurposed office supply item! The project is a DIY from Hakai and Jili, shown off first in their Small Cool Entry waaaay back in 2006: Hakarl and Jili's Bold Bright Moves.
Meg and Ross added tons of pattern and color to their bathroom using the age-old technique of applying fabric to their walls instead of paper. Check out the post on the transformation: Meg & Ross' Updated Bathroom. They used the easily reversible fabric starch method, as explained in this step-by-step how-to post: How To: Make Removable Fabric Wallpaper.
If you're looking for something a little less messy than starch and fabric, yet still easily removable, you're in luck. There are a multitude of ready-made options available now, from peel and stick wallpapers to murals and decals. Ten of the best are included in this shopping sourcelist: Peel and Stick Wallpaper & Coverups for Renters.
The New York Times included a great looking, simple use of vinyl wall decals in this makeover story: For Young Newlyweds, a Lighter Look. Using the decals to create the wide horizontal stripes makes for an inexpensive, bold graphic look that's memorable, defines the space, yet is incredibly easy to reverse.
Another alternative is to treat traditional wallpaper as oversized artwork, covering up a swath of that landlord-white wall real estate with loosely hung or framed panels of paper. Several ideas on this theme: Hanging Wallpaper Without Gluing It.
House Tour participants Chelsea and Sean embraced the temporary nature of their rental friendly wallpaper solution by going with a quirky, humorous pattern. They tacked up wrapping paper sheets to brighten a blah entryway. The project adds personality and fun, and will be a breeze to remove when the time comes. Spotlight on this one: Rental Friendly Wallpaper Solution. Have more ideas to share? Let us know in the comments below… Images: 1 - 3, 7, Apartment Therapy, as linked above, 4. Tempaper 5. Emily Weinstein/New York Times