The Doctor Who interactive game City of The Daleks was downloaded 524,000 times in 12 days

"Publisher BBC Wales Interactive says more than half a million people downloaded the first episode of its Doctor Who: The Adventure Games series in the first 12 days after the PC game released for free in the UK.
As with the other episodes, the first release, City of the Daleks, was originally intended as a full and legitimate Doctor Who episode for the sci-fi television program, and features the likenesses and voices of the show's stars Matt Smith and Karen Gillen.
Doctor Who's head writer and executive producer Steven Moffat, as well as many others involved with the production of the show, is also involved with the publicly-funded game project, as Sumo Digital (Sonic & Sega All-Stars Racing, Virtua Tennis 2009) handles its development.
Along with the 524,299 UK gamers that downloaded City of the Daleks, the publisher notes that the BBC's main Doctor Who site received a week-on-week 67 percent increase in traffic from unique UK visitors during the seven days after the game was released."
Source: Gamasutra, 18th June 2010