You've seen 'em. Out by apartment house dumpsters.
Here's something fun:
Cover the remaining three sides with reflective film. Fashion a lid out of whatever. Place the sucker in the breakfast room window and dump bird seed on the bottom.
Little birdies, not bothered by their own reflection and unable to see you, will come virtually into your house to have their breakfast while you're enjoying yours.
Saw this set up at an Audubon Society sanctuary and thought it would make a neat week-end project.
Have fun.