On stays through April 15, 2018, SPG has a promotion in which you can earn double Starpoints beginning on your second stay, at SPG hotels and resorts participating in the Promotion. You can also earn an additional 500 bonus Starpoints beginning on your second stay if your stay includes a Friday or Saturday night.
You must register by 11:59 p.m. Eastern Time (ET) March 31, 2018 to take advantage of this promotion. You can learn more about the promotion here.