edit: bad word. This isn't working. It lets me vote again, but the total vote count isn't going up.
Could someone younger than I please post the secret?
OK, I work with far too many operating systems, so I can't keep track of how to clear cookies. But here's what is working for me, and you might want to make note of it for similar situations.
I'm on Windows 7 Professional, running Mozilla Firefox at the moment; IE when I have to.
First click on the link that CarbonVol supplied and vote. Close the window.
In Firefox, click on Tools --> Options --> Privacy. In the lower half of this window, you will see a link to "remove individual cookies." Click this link, and another window will open. Unless you want to wipe out all your saved logons, passwords, etc., type "tailgating" in the search window at the top. You'll probably bring up around 8 different cookies. As each one is highlighted, click the "Remove Cookie" button at the bottom left (NOT Remove All Cookies!) until all cookies called tailgatingideas-something are gone.
Now go back to the window where you voted before, and hit the refresh button (circle with an arrow) in the browser window. Your page will refresh, and you can vote again and again, using this method, apparently as long as your patience will hold out.
Good luck CarbonVol!