Yesterday, I celebrated my 35th birthday. Normally, not a big issue. This year, it was a bit different: the Department asked me to give the keynote lecture at the Student Research Day 2017 – a day where all our students present their research findings (the first year students present on their work for the Social Problems course, the second year students present findings of their Learning Project, whereas the Bachelor, Premaster and Master students present their thesis). I advertised to present my research on immigration and the welfare state. However, I quickly switched topic to something more unfamiliar but extremely timely: the sociology of birthdays! The presentation can be retrieved from SlideShare.