DIY: How to create a water fountain - includes excellent instructions and a video.
No pool waterfall -- I like this a lot. You get the sound of the water w/out the pool slime
This pool noodle floating cooler only costs $1.99.
Drill holes into your fence and replace them with marbles.
Use rope lighting to line your garden.
They start at about $2-3k, which isn't exactly cheap, but they are significantly cheaper than a pool. And safer, too, because there's less risk of drowning.
Along walkway - put on timer
Can't afford that dream deck or in-ground pool you're dying for? There are still ways to get a beautiful backyard that's perfect for entertaining.