Matt Stempeck of the MIT Media Lab created LazyTruth, a "Gmail gadget that surfaces verified debunks when you receive a chain email." He says:
Each year, we gather around the table with large branches of our family tree. As the night wears on, family updates give way to dramatic retellings of the bizarre email chains you've been forwarded all year. This year, as part of your IT duties, consider inoculating the family machines with LazyTruth. The Chrome extension works right within Gmail to provide summarized debunks of common viral emails. You get fewer forwarded emails, and MIT researchers get to learn how this stuff spreads in the first place.