Act #13: EXpress yourself
The French expression of today is an exclamation of surprise, disbelief or even of admiration. It is je n'en reviens pas ! In the expression the en is standing for whatever it is that you find so surprising. It literally means "I’m not coming back from it" and can be translated as "I can’t believe it" or "I can’t get over it". The register of the expression being informal, it would only be used in spoken French and in the exclamative mode.