We present an overview of our current understanding of the interactions between like-charged macro-molecules, mediated by mobile neutralizing counter-ions. A single dimensionless parameter qualifies the regime as weakly or strongly coupled, and drives qualitatively different features with the possibility of strong attraction between like-charged bodies. Particular emphasis will be put on a recently introduced strong coupling expansion, for both two- and three-dimensional systems. Likewise, Thomson's plum pudding model will be revisited.