MATHEON, a joint research center of the three Berlin universities (Freie Universität Berlin, Humboldt-Universität zu Berlin, Technische Universität Berlin), is creating an Advent calendar again this year. With one math puzzle per day, it is aimed at high school and college students as well as any interested adults. Available in both German and English, it supplements the "Math in Advent" calendar published online by the German Mathematical Society, which creates calendars for grades 4 through 6 and 7 through 9 (also available in English and German). All three calendars this year were created under the motto "More than sums" and are under the patronage of the German Federal Minister for Education and Research, Prof. Dr. Johanna Wanka. The MATHEON calendar was launched in 2003, and the ones for younger school children were started in 2008. Participation is free; the award ceremony – with numerous prizes – will take place on January 26, 2018, at Technische Universität Berlin.