I just read this in Impact mag yesterday. I wasn't even aware the One Shows were on, but the Halo 3 "Believe" campaign won a Best Of Show at this year's One Show.
“The ‘Believe’ campaign catapulted Halo 3 from an ordinary video game into a worldwide cultural phenomenon due to its ability to build an emotional rapport with the audience,” said Mary Warlick, CEO of The One Club. “The innovative stream of interactive TV, Web and cinema advertisements was an inspired approach that successfully attracted an audience beyond the typical gamer.”
View the "Believe" videos here - http://www.xbox.com/en-US/games/h/halo3/believe/default.htm or do a YouTube search.