Xbox Live services (namely friend lists and social serveces) are currently being impacted by an outage, making the features unavailable to players. Part of the users impacted report further functions on Xbox One and 360 affected, even if it doesn’t seem to be the case for everyone.
A DDOS (distributed denial of service) group claimed responsibility for the attack, also threatening further action for Christmas. Of course there’s no way to verify the legitimacy of the claim.
Looks like some really don’t have anything better to do with their evening.
Update: the service seems to have resumed its normal activity.