The version that I learned a long time ago and memorised is this one.

God grant me the serenity
To accept things I cannot change
Courage to change things I can
And wisdom to know the difference

By way of Wikipedia, I learned it actually came from Reinhold Niebuhr and here is the full version.

God, give me grace to accept with serenity
the things that cannot be changed,
Courage to change the things
which should be changed,
and the Wisdom to distinguish
the one from the other.

Living one day at a time,
Enjoying one moment at a time,
Accepting hardship as a pathway to peace,
Taking, as Jesus did,
This sinful world as it is,
Not as I would have it,
Trusting that You will make all things right,
If I surrender to Your will,
So that I may be reasonably happy in this life,
And supremely happy with You forever in the next.

Amen