Via Priority Club Insider, Priority Club is offering double points or double miles beginning with your second stay from May 16 through August 15 (stays at Candlewood Suites and Staybridge Suites earn double points beginning with first stay during the promo period).
Registration is required. Priority Club Insider suggests waiting until May 16 to do so, in case a better offer comes along that is mutually exclusive from this one. Though I suspect most folks will benefit from just registering and forgetting about it, rather than setting a calendar reminder to register next month.