Well, there's "play hard ball" meaning to be tough or even ruthless, or at least serious. I always took this to be from baseball, where the ball is hard, as opposed to softball, where it is, uh, soft, and thus not nearly as dangerous.

In medicine, when we're on call at the hospital for new admissions (as I am tonight, lucky me), if we should be so fortunate as not to have a single admission all night, then the next day we can boast to our coworkers that we had a "no hitter." We've already had two admissions tonight, so alas, it won't be a no hitter.

In Little League we used to tease guys who struck out by calling them "Special K," after the cereal and the fact that a strikeout is recorded in the scorebook as a "K."