Systems biology is a lively interdisciplinary research field that has received considerable attention in recent years. While traditional molecular biology studies the various components of a biological system (genes, RNAs, proteins,...) in isolation, systems biology aims to understand how these components interact in order to perform higher-level functions. Mathematical modeling then plays a major role not only in capturing and analyzing complex networks governing biological processes, but also as a way to verify hypotheses based on observational evidence and in designing efficient experiments to further the understanding of the system. The goal of this project is to pool our knowledge on discrete, deterministic and stochastic modeling of biological systems to pave the way towards efficient hybrid models (discrete/continuous, deterministic/stochastic) for elaborate biological networks.