Lars Halvard Halle Title: "Motivic zeta functions of Calabi-Yau varieties" Abstract: Let K be a complete discretely valued field with residue field k, and let X be a smooth K-variety with trivial canonical sheaf. To such a variety one can associate an invariant known as the "motivic zeta function" of X. This is a formal power series with coefficients in the Grothendieck ring of k-varieties, which measures how the set of rational points of X varies under ramified extension of K. I will talk about joint work with Johannes Nicaise, where we investigate properties of motivic zeta functions. In particular, the case of (semi)abelian varieties will be discussed.