Major Nelson Shares some information on this new demo for XBL:
Content: MX vs. ATV Untamed Demo
Availability: Not available in Hong Kong, India, Japan, Singapore or Taiwan
Dash Text: [ESRB: E (Everyone) MILD VIOLENCE] The best selling offroad franchise returns! Own the offroad with the official gameplay demo for MX vs. ATV: Untamed!
Size: 911.78 MB