The first time Kelly taught the course, in 2008, his students confected the life of Edward Owens, mixing together actual lives and events with brazen fabrications. They created YouTube videos, interviewed experts, scanned and transcribed primary documents, and built a Wikipedia page to honor Owens' memory. The romantic tale of a pirate plying his trade in the Chesapeake struck a chord, and quickly landed on USA Today's pop culture blog. When Kelly announced the hoax at the end of the semester, some were amused, applauding his pedagogical innovations. Many others were livid.

Critics decried the creation of a fake Wikipedia page as digital vandalism. "Things like that really, really, really annoy me," fumed founder Jimmy Wales, comparing it to dumping trash in the streets to test the willingness of a community to keep it clean. But the indignation may, in part, have been compounded by the weaknesses the project exposed. Wikipedia operates on a presumption of good will. Determined contributors, from public relations firms to activists to pranksters, often exploit that, inserting information they would like displayed. The sprawling scale of Wikipedia, with nearly four million English-language entries, ensures that even if overall quality remains high, many such efforts will prove successful.

Last January, as he prepared to offer the class again, Kelly put the Internet on notice. He posted his syllabus and announced that his new, larger class was likely to create two separate hoaxes. He told members of the public to "consider yourself warned--twice."

This time, the class decided not to create false Wikipedia entries. Instead, it used a slightly more insidious stratagem, creating or expanding Wikipedia articles on a strictly factual basis, and then using their own websites to stitch together these truthful claims into elaborate hoaxes.

One group took its inspiration from the fact that the original Star-Spangled Banner had been sewn on the floor of Brown's Brewery in Baltimore. The group decided that a story that good deserved a beer of its own. They crafted a tale of discovering the old recipe used by Brown's to make its brews, registered BeerOf1812.com, built a Wikipedia page for the brewery, and tweeted out the tale on their Twitter feed. No one suspected a thing. In fact, hardly anyone even noticed. They did manage to fool one well-meaning DJ in Washington, DC, but the hoax was otherwise a dud.

The second group settled on the story of serial killer Joe Scafe. Using newspaper databases, they identified four actual women murdered in New York City from 1895 to 1897, victims of broadly similar crimes. They created Wikipedia articles for the victims, carefully following the rules of the site. They concocted an elaborate story of discovery, and fabricated images of the trunk's contents. Then, the class prepared to spring its surprise on an unsuspecting world. A student posing as Lisa Quinn logged into Reddit, the popular social news website, and posed an eye-catching question: "Opinions please, Reddit. Do you think my 'Uncle' Joe was just weird or possibly a serial killer?"