We introduce an original definition of character varieties associated to a punctured compact oriented surface with at least one puncture per boundary component, and one of the Lie groups (C * ) N , GL N (C), SL N (C), Sp N (C), O N (C) or SO 2N+1 (C). These character varieties are affine Poisson varieties which coincide with the Culler-Shalen character varieties when the surface is closed but are different when the surface is open. The main motivation for this generalization is the fact that these character varieties have a nice behaviour for the operation of gluing two boundary arcs of a punctured surface. Our character varieties admit triangular decompositions, similar to the decomposition of Lê's stated skein algebras. We identify the Zarisky tangent spaces of these varieties with some twisted groupoid cohomological groups and provide a generalization of Goldman's formula for the Poisson bracket of curve functions.