I guess, one the most entertaining events that I remember, was those that happened on the way to Heatran. At the time I didn't know Heatran even was in that mountain, and when I finally reached that empty room I was so greatly annoyed because of all the time I spent, fighting my way to nothing. Though after the events with Buck stealing the 'treasure' and that, and after I returned to the room, I was so glad to see Heatran there. So I guess it wasn't that entertaining in itself, untill the reward was shown, though I don't really remember that many of the other events in the games, so I'm just gonna go with this one >_<