I recieved an email from <email@example.com> with a link to win a trip to Universal Studios. When I clicked on the link, the site was blocked.
This site is blocked due to a security threat that was discovered by the Cisco Umbrella security researchers.
According to Whois.com, the domain xfinityadventure.com is private and does not belong to Comcast/Xfinity, created only a couple months ago via GoDaddy. Until someone from Comcast can verify its authenticity, I would be wary.