By Lydia Beyoud and J.J. McCorvey, Bloomberg News The Commodity Futures Trading Commission unveiled a proposal for prediction markets Wednesday that would crack down on bets related to war, terrorism and assassination. The CFTC plan also proposed narrowly defining some "gaming" - the category that helped launch the surge of sports-related prediction markets 18 months ago - to be games of "pure luck." That definition would allow the majority of sports contracts now trading to continue.