Doritos have released two free games on xbox live arcade:
"Harm's Way is a fast paced, action packed race where both drivers and snipers need to team up to win the race. As the sniper, you need to blow-up the competition. As a driver you need to finish 3 laps first."
"Doritos Crash Course is a fast-paced, funny, obstacle course game show for your Avatar to compete against your friends and family over XboxLive. Play through 15 exciting platformer levels across 3 different countries. Compete against your friends and family up to four players over XboxLive and local split-screen."
They have both been up on the Market Place for a while now, but I haven't seen it mentioned on HotUKdeals.