The upcoming Starwood Preferred Guest promotion was just leaked and it looks like between May 27 and August 30, 2017 you can earn either double or triple points. The major caveat is that your stay must be 2 or more nights.
- Triple points: If your stay includes a weekend night (Friday or Saturday)
- Double points: For all other stays
As of right now you cannot register for the promotion since it is not officially launched. There are also no other terms, such as excluded hotels, etc. I am sure more details will come soon!