Microsoft are offering Xbox LIVE users who do not have a Gold account free access to the Gold services for this weekend only.
This is what Major Nelson posted:
We’re also unlocking our Xbox LIVE Gold subscription service in various regions from Friday, June 1 through Sunday, June 3 – no Xbox LIVE Gold membership required for this time. Through this promotion, anyone In the U.S., Japan, Mexico, Brazil, Colombia and Chile with an Xbox will be able to enjoy multi-player gaming experiences featured on the Xbox LIVE service.
So if you are in one of those regions and don’t have an Xbox LIVE Gold subscription, why not take advantage while you can.