On the occasion of the foundation of the Institute for Discrete Structures and Symbolic Computing IDSR and within the framework of the Tübingen-Stuttgart Seminar (TüSS), Prof. Frederik Witt and Prof. Menolf Geck invited to a colloquium on algebra and geometry. The lecture of Prof. Gunter Malle (University of Kaiserslautern) was dedicated to the topic "Groups, Representations, and Decomposition Matrices". Afterwards Prof. Klaus Altmann (Freie Universität Berlin) spoke about "Infecting Z^2". The colloquium was rounded off with a dinner.