This is really hard for me to answer, because the role-playing I experienced from around the start of Catskills until Trammel was like one really long, super awesome party in my memory. There were a lot of great story-lines, encounters, conflicts, wars, etc., that it's too difficult to recount them all. That's not to say there weren't some really great memories post-Trammel either, it just wasn't exactly the same.
One great random memory that always sticks out was back when I was playing a member of Clan Gunn, who were the rivals of Clan Stewart of the Highland Sosarians. Some people might remember Lachlan Stewart of that guild, the guy who brought us Kent's Last Pint in Yew. Anyway, the whole fiction behind the Highland Sosarians was that we were natives of Cove who resented Britannia for taking over their homeland. During the summer of 1998, the Kingdom of Winterfell decided to take up residence in Cove, and some of the Highland Sosarians were pissed (in-character) about it. One day, there was a caravan event (I think organized by Rutger Dag of the Paladins of Trinsic) that was making it's way between Cove and Yew. Clan Gunn decided to sabotage it, so my Gunn character found the Town of Yew Militia (not to be confused with the later Yew Militia), a group that was made up of Shadow Clan alts. She was an innocent looking teenage girl (at least on the outside), and convinced the Militia men that the caravan had been possessed by demons and were on their way to destroy Yew. We tricked the two groups into fighting, and were able to disrupt the caravan and strike a blow in the name of freedom for Cove. It was totally spontaneous, unplanned, and random fun, and most importantly, no one complained after the fact!
I also still laugh about the time Judas kissed Whorrid Inc. of the Undead during some good guys vs. bad guy battle, only because it was kind of screwed up and unexpected.