Canadian Football League
The CFL or Canadian Football League is the only professional football league currently active in Canada. Canadian football differs from its American counterpart in that it has a larger playing field (110 yards X 65 yards), twelve players per side as opposed to eleven, and three downs to move the ball ten yards, as opposed to four. Additional differences include in the CFL if a receiving team does not play the ball, the kicker and his teammates can attempt to catch and advance the ball. The Official CFL Rule book is located on their website .
The teams of the CFL compete for the Grey Cup, named for the Canadian Governor General Earl Grey. The winners of the Grey Cup since 1909 are posted on the CFL's website here: 
It also can stand for compact fluorescent lightbulb, a new technology meant to replace incandescent lightbulbs, discovered by Thomas Edison. CFL's use less energy than incandenscent lightbulbs, as the power usage is much less to provide the same amount of light. CFLs contain mercury, which complicates their disposal.