Yesterday I found myself out of the washers I needed for a project and an unwillingness to go into town just for that. Then I remembered an episode of Cross Country Checkup about Canada's phasing out of the penny, and a guy who called in to point out that pennies cost a penny but washers cost 5 to 10 cents. He had taken to making washers out of them.
I grabbed my drill and a bucket of pennies I had sitting around and tried it out. I was in a hurry, and the project didn't require precision, so I didn't worry about precise hole placement. Worked like a damn!
Tips: Older pennies are made of pure copper and are harder to drill through. Newer ones are made of a softer metal. Go for those.
If you're using a drill rather than a drill press, drill through one and let it ride up the bit. Drill through consecutive ones and let those ride up the bit too, and then use a thin piece of whatever to push against the pennies as you retract the bit. This will save you time.