The second Olympics I remember were in Seoul. Again I don't remember a huge amount. The main event was the men's 100m which pitted Ben Johnson against Carl Lewis. Ben Johnson whooped him. That isn't the bit I remember most though. The most memorable thing was when he was outed as a cheat. I was 9 and had no idea what an anabolic steroid was but when the woman with the funny voice announced the problem with "the sample of Ben Johnson, Canada" I learned quickly. The race is below (I couldn't find the cheating announcement).
Other highlights were Flo Jo's nails, Greg Louganis breaking his head, Adrian Moorhouse winning the breast stroke, Sean Kerly and Imran Sherwani in the hockey and wondering what the hell Synchronized Swimming was all about.