Both NBA 2K17 and the forever-entertaining car football game, Rocket League, are free to download this weekend as part of Microsoft's Multiplayer All-Access Weekend. Once downloaded, players will have infinite access to the game's multiplayer component until the end of the weekend.
The event will run from February 16th till February 19th and will also see Xbox Live Gold membership requirements set aside for the weekend. That means that even without a gold membership, players on the Xbox One and Xbox 360 will be able to play online with their friends.
Assuming you end up liking either of the multiplayer giants, NBA 2K17 and Rocket League are both currently being sold at a reduced price on Xbox One.