If your backyard is looking dull, consider brightening it up with a small fountain. DIY web site Instructables has a guide to making your own out of pretty much any structure you already have lying around.
The basics of a fountain are the same no matter what you use—you'll need a sculpture, some water (obviously), and a pump to keep it all flowing. The sculpture can be anything as long as it can handle water constantly flowing over it—if you already have some sort of lawn ornament lying around, you can probably mod it to fit your fountain. Otherwise, large, flat stones make a pretty zen structure.
You'll need quite a few things to put the fountain together, but nothing a trip to a hardware store won't solve—you'll need a submersible pump, a copper pipe, and a waterproof tub, as well as some screen, some decking, and a few various valves and adapters. That sounds like a lot, but putting it together isn't very difficult—in fact, the hardest part is probably digging the hole in which you'll put the tub (and drilling a hole for the pipe in whatever stones or ornament you're using). Hit the link for the full instructions, and if you've ever tacked a similar project, let us know your favourite fountain structure in the comments!
How to Make a Garden Fountain Out of, Well, Anything You Want [Instructables]