The Last Week Tonight host dug into the rapidly expanding, poorly regulated free-for-all of ‘prediction markets’ like Kalshi and Polymarket The Last Week Tonight host dug into the rapidly expanding, poorly regulated free-for-all of ‘prediction markets’ like Kalshi and Polymarket O n the latest Last Week Tonight, John Oliver examined the surging field of so-called prediction markets, which have seen exponential growth in recent months with billions of dollars of bets every week for questions