NBC's Heroes may have hit a season low for the second week in a row last week, but it was the most downloaded show on BitTorrent sites, according to TorrentFreak.com, which says that its data are collected "from a representative sample of BitTorrent sites." According to the data, the second most-downloaded show was Fox's Prison Break , which has also seen a significant audience downturn this season. Each show was downloaded more than a million times, mostly from outside the U.S., TorrentFreak said. Coming in third was Showtime's Dexter , followed by Fix;s Terminator The Sarah Connor Chronicles, whose ratings have been so low this season that several analysts have predicted imminent cancellation. Rounding out the top five was ABC's hit drama Grey's Anatomy.