Casimir Pulaski Day. If you grew up in Illinois in the 1980s or 1990s (or, if you raised a kid at the time), you probably remember a school and government holiday — the first Monday in March — that most of the rest of the country does not observe. https://www.wbez.org/shows/wbez-news/the-rise-of-casimir-pulaski-day/f7885e2e-7df6-47f0-bdda-610b445c11af