another thing you can do with something common to many households, beer. My friend and co-worker Sullivan turned me on to this. It's her art, not mine, i just thought i'd post the idea.
a half rack of beer
innate artistic ability (or the desire to "spruce up the place a bit" without prostituting your art.)
bag (i suggest paper grocery, that way you can keep these in one while keeping stencil in other...but that's another project.)
Step 1: Get an Empty Beer Can. Tall Boys Are Better But Anything Works.
Make sure to get the top and bottoms to fold on the same side, resulting in a fairly smooth side and a crappy side.
Step 2: Now Paint the Flat Side
I can't possibly begin to explain art to you, so you're on your own here. sorry.
don't forget to primer the heck out of this side....it's really for the best you know.
Step 3: Get a Big Bag Full of Completed Beer Cans
and nail them to some telephone poles, small children, moving cars, or churches. whatever, just put them out there!
The cool thing about these is they last a LOOONG time, especially if you nail them high. i suppose there might be some way to crush the can with magnets in it so as to just toss them up at metal lightposts, but i've never tried it....or thought about it until just this second really.