The WinStar River Poker Series has a long history dating back to 2012, which is when Aaron Massey topped a 1,396-entry field to win the title and $651,559 first-place prize. On Friday, the 2019 Labor Day River Series $1,500 buy-in, $1,500,000 guarantee Main Event will get underway, and the PokerNews Live Reporting Team will be on hand to capture all the action. WinStar Casino is set to kick off one of the most-anticipated mid-major poker tournaments of the year. Remaining 2019 Labor Day River Series Schedule.2019 Labor Day River Series Side Event Winners.