Photo by Jennifer Dickert.
Instead of going through a lot of trouble to avoid the waterworks, weblog Daily DIY says you can stop tears by merely putting your tongue on the roof of your mouth while you're cutting. Whatever you do, though, don't breathe through your nose—breathe through your mouth. You may look a little silly, but it barely requires any work on your part, and it's sure to be a conversation starter with your dinner guests.
I couldn't find any definitive information about this one, but a quick Google search shows that quite a few people swear by this solution. If any of you cooks out there get a chance to chop up some onions—or you already do this—give it a try and let us know how it goes in the comments.
Onion Tears No More [Daily DIY]