unexpectedly, suddenly and surprisingly

the whale tail is the shape formed when a g-string rides up high over a womans trousers

Strange, and unexpected. Lucky/Unlucky.

Most baseball batters are right handed (therefore swing the bat from right to left) and hit a ball out into left field.
The batter immediately drops the bat and runs to the right to get to first base.
It is quite difficult for a good left field ball to hit the ground in far left field, get picked up, and thrown, accurately across the entire field to the first baseman, before the batter can get to first base. If this does happen, its an incredible throw, from way out in left field. Totally unexpected.

out of left field comes from when wrigley field was first built. In left field there was a insane asylum so when something crazy or unforseen happened it was termed, "out of left field"

some kind of baseball slang referring to an unexpected event.

(help me out here UDers.. where did this phrase come from and what does it really mean?)