Documentation for Fake News Fitness 2.0 can be found here: docs.fakenewsfitness.org
Between FactCheck.org, Snopes.com, the Washington Post Fact Checker and PolitiFact.com, it’s likely at least one has already fact-checked the latest viral claim to pop up in your news feed.
If you'd rather not check those out specifically, just Google the URL of the article and see who links to it, and whether any of these seem to be calling it a Hoax. If that doesn't work, but if the article is clearly syndicated (it was not written by a reporter or author employed by the site you found it on), Google the title or a chunk of text, and see where else it appeared -- and whether THAT article was considered a hoax.