Our guest room was dark green and boring.  We brightened it up with green-gray paint and white bedding.  I also made bright new pillows and curtains, and covered an old chair.  We've also replaced the covered canvases with an old painting we bought at an estate sale and had framed.

Our upstairs bathroom was a sickly yellow, and we quickly painted it bright green.  After living with the green a while, we painted it a medium blue-green to fit in with the rest of our house better.  I made a fun shower curtain and got some new art on the cheap.

 

The office was a dark teal color.  We painted it over with a very light blue gray, and made curtains with some bold fabric. We added new book shelves and a small sofa.  Still on our list?  Storage solutions for the computer, TV, and video game stuff.