Full Idea
Nietzsche is overwhelmingly concerned with how to respond to nihilism, and he offers the concept of eternal return; the Overman is one who can affirm over and over that one is equal to meaninglessness, without turning to despair or idols.
Clarification
The Overman (übermensch) is a person above conventional morality
Gist of Idea
Nietzsche says facing up to the eternal return of meaninglessness is the response to nihilism
Source
report of Friedrich Nietzsche (The Gay (Joyful) Science [1882], §342) by Simon Critchley - Interview with Baggini and Stangroom p.192
Book Reference
Baggini,J/Stangroom,J: 'New British Philosophy' [Routledge 2002], p.192
A Reaction
I agree with Critchley that this is not much of a recipe for ordinary people's lives, and I don't even find it very congenial for a tough-minded philosopher. We should make the best of the cards we are dealt, however feeble they may appear.