The many roleplays, the auctions, killing monsters and suddenly having the NPC server go down, Proglin's Tournaments, many quests, the Introduction system, seeing devs come and go, repeatedly trying and then giving up training in the Magic Ways, The Great Shift of Ojaveda, The Eclipse, the introduction of Crafting; "The Gold Rush", the subsequent Platinum Rush in Gugrontid, the big Money Duplication exploit, the introduction of the second server. And of course the gargantuan amount of bugs fixed. (and many more introduced)
Ah, time, how fast it goes.