Heart Day is a day in early Q1 that is meant to celebrate romantic love. In proper Stem City noble fashion, its true intention is to sell more products via social pressure and to sell more sex to those lonely enough to seek out something. It has no major history beyond being a marketing scheme made in XX533.
Halloween is not something really celebrated in Stem City, it is the only major holiday celebrated in Gillsway. The day in which Q4's lights are displayed in the sky is one where the citizens fashion costumes made of scrap in an attempt to wow each other. It's become mainstream because the Gillsway founders immigrated from a planet where a holiday of the same name is celebrated every year.
Connectionay marks the day long ago the Nexus finished construction and was officially open for business. Great value sales happen in most businesses for a week beforehand, and on Connectionay, it is expected to give those close to you presents. It isn't uncommon for the noble neighborhood to be covered in special tram-related decorations and for folks to be dressed in fluffy festive outfits and drink out in public.
One week at the end of every quarter ends in an Ahsonov Ball. During this week, Shroom's Academy is shut down and many businesses are open half as often.