Just been browsing the board and hit upon this basbeball thread. And since baseball season just opened two days ago (and since I'm hooked on the sport like a drug no matter how much they denigrate the fans with their greed...in short, I'm a baseball nut! No excuses!), I thought I'd offer a few phrases off the top of my head after reading through the thread...and I'm sure I'll be back with more!

An expression you hear often when somebody makes a mistake is..."and the big 'E' lights up on the scoreboard!"
The "E," of course, meaning 'error' in basball parlance.

One obvious term overlooked is "throwing a curve" used in a variety of ways. For instance, if you're cautioning someone about about a certain party's nefarious business practices you might say, "Watch out, or he'll throw you a curve." Also, if you're pleading fairness, or kidding a friend about giving you a hard time, you might say "don't throw me any curves" or "don't start throwing curves at me, now." But this expression is used in common parlance
in a frequent enough variety of ways that we've all heard or used it in one form or another, so I won't try to list all the contingencies here.

"Say it ain't so, Joe!" A catchphrase attached to the name of anyone we hold in esteem who suddenly disappoints us with untoward activity. First popularized, of course, when baseball great (and some people argue the game's greatest hitter ever), Shoeless Joe Jackson, was implicated in the Blacksox Scandal of 1919 when his team, the
Chicago White Sox, threw the series in a gambling fix. He was never convicted, but nevertheless banished from the game for life by baseball commissioner Judge Kennesaw Mountain Landis, a great career never realized. And all the young boys of the day who looked up to him in Chicago and elsewhere started tossing that phrase at him
when they met, the papers picked on it and made it a headline, and the rest is linguistic history. Even when Pete Rose was busted for gambling in '89 the papers bellowed "Say It Ain't So, Pete!"

"Otherwise you're just swinging at air!" Another expression for spending your energies in the wrong places, missing the mark, etc., derived, of course, from the batter taking a swing at a bad pitch, missing it by a mile, and coming up embarrassingly empty. Or, "you're swinging at the air!"--various forms

"Headin' for home!" When one is closing in on an eagerly sought goal or finishing an important task. Or, as formerly pointed out, the long-hoped-for goal of adolescent boys' lecherly petting (the sweet dream, as it were!--sorry ladies...but we were all there, once, in those days of, uh, innocence!) Derived, of course, from the all-important goal of rounding third-base and heading down the base-path to home plate to score the all-important run.

Well, that's it for now...(or 'enough' I should say) Ah, baseball!...It brings the loquaciousness out in me! I'm sure I'll be back with more, and to peek at any responses...if anybody's still hitting this thread by then.