What does this expression mean?

"Thanks for hitting the ball into my park for once "

It's a vague allusion to baseball, but doesn't correspond to any literal event in that game. The sentence means ``Thanks for giving it to me for a change'' where the `it' is something determined by the context of the sentence.

I get the first part "thanx for giving it to me"
but not the 2nd one "for a change"
thnx anyways

"for a change", "for once" - means that that's not what usually happens

Example of the above:

"We always do what you want to do. We should do what I want to do for once."

"I'm tired of cooking dinner every night. Let's eat out for a change."

thnx Deborah, I liked how you provide an example :)

You're welcome!