The idea first came to Jeff Curtin and Adam Schatz the way so many awesome ideas do: in the form of a rock opera.

Last January, the Brooklyn-based musicians were considering crafting a sweeping, "Tommy"-style tribute to "Lost," their favorite TV show. But just before the ABC drama's fourth season, they had a thought. What if they wrote a new song after each broadcast that summarized the key events in the latest chapter of the stranded-on-an-island saga? What if they posted the tracks on their MySpace page? And what if they called themselves Previously on Lost, an homage to the plot summaries that precede each episode of "Lost"? Would people click and listen?

The answer to that question was a resounding, "Dude, yes!"

What began as an online experiment has morphed into a career for Curtin and Schatz. After building a following for the "Lost" musical recaps, the band's summer included appearing on National Public Radio, performing in New York, Los Angeles and San Francisco, meeting "Lost" producers (fans, naturally) and selling the complete 12-track opus, "The Tale of Season 4 and the Oceanic Six," on iTunes.

Suddenly, a band that draws its material from smoke monsters finds itself with blogosphere buzz, a smattering of live gigs, and a reputation as perhaps the best-known (though not only) recap rock band in America.

What does the music sound like? There have been few mainstream reviews, but Gawker.com calls the result "Rockapella guest-starring on the toddler show 'Yo Gabba Gabba.' "