A company looking to hire recruiters decided that many potential hires played Team Fortress 2. They paid prominent players to become "ambassadors" and the players changed their names to the company's job listing url, where I found this swell widescreen wallpaper:
They also created a poster/advertisement for players to post throughout the game world. There's no mention of whether Valve objected. Via.
*Previously: Team Fortress 2 paper toys.