Ok, let's see:
Atlanta 1996 - Magic day 21st of July. Three gold medals for Poland: Ryszard Wolny (greco-roman wrestling 68kg), Andrzej Wroński (greco-roman wrestling 100kg) and Pawel Nastula (judo 95kg). Poland was even leader of medal table I believe because we had four golds at that time (Renata Mauer get one in 10m air rifle day before that) but I'm not sure.
Nagano 1998 - To be honest I don't have one. It was time I was still very young and I was watching olympics only because of polish athletes and we wasn't very good in winter sports back then (but there was some good starts like Andrzej Bachleda in alpine combined or men's biathlon relay)
Sydney 2000 - Robert Korzeniowski gold in 20km race walking. He was second when he cross the line but after the race winner Mexican Segura was DSQ for running. Korzeniowski found out about that during interview for polish television.
Salt Lake City 2002 - Bjoerndalen four gold medals in biathlon, Lajunen three golds in nordic combined and of course Steven Bradbury.
Athens 2004 - Magic day for Argentina. Two golds, one in basketball, one in football. First golds from a very long time.
Torino 2006 - Shaun White gold in halfpipe and Martins Rubenis gets first winter medal for Latvia.
Beijing 2008 - Bolt beating Johnson's WR on 200m and three golds of Chris Hoy.
Vancouver 2010 - Kowalczyk beat Bjoergen in 30km and Steven Holcomb gold in four-man bobsleigh.
London 2012 - Opening ceremony and Felix Sanchez gold.
Sochi 2014 - I don't know, it was magical olympics. Two golds of Kamil Stoch, gold of Zbigniew Brodka (who wins it with advantage of 0,003s!), gold of Justyna Kowalczyk (won with broken foot). And ladies first ski jumping competition.
Rio 2016 - Wayde van Niekerk WR on 400m and Ruth Beitia gold in high jump. And also WR of Anita Wlodarczyk in hammer.
Pyeongchang 2018 - Two gold medals in two-man bobsleigh for Kripps and Friedrich, David Gleirscher gold in men's singles luge and German ice hockey team.
Tokyo 2020 - Opening ceremony because when it'll begin I'll know that everything is just fine.