So this is an old post, and I'm a new user... after reading the theme for of 'favorite role playing moments', I had to add one of my funniest and memorable moments of D&D and sign up for the forum.
A few years ago, we were playing a normal D&D type session, which involved some of our oldest and most highly leveled characters. We had 4 high level mages who all had apprentices (spelling?) all centered in one particular tower, which, in typical noncreative DM fasion was under seige. It was a lame attempt at killing us off due to our characters being too overpowered for our DM to keep up with (and potentially the fact that we were all evil and had just wiped out several small villages for some reason or another). Well, our DM had this group of warriors who were notorious in our game, Black Knights or some such, with millions of hit points and magic resistance, making them mage KILLERS... and he'd send tons of them after us to try and kill us... climbing ladders, ramming the front door (like knocking was just TOO polite of an option, geesh) and the like. So we decided to use a few of our mages' tower's designs to our advantage and abuse some D&D rules to get back at our DM. We slaved for a few days, scribing scrolls, scrolls, scrolls, every available mage scribing scrolls for a few days doing this while the tower's defenses held everyone out... as soon as the defenses were crumbling and Knights were rading the halls, every mage (there were like 19-20 total) mass casted HASTE on our attackers from safe spots in the tower, behind barriers that kept them safe from attack, yet allowed us to get close enough to them to be within spell range. So our DM was a bit confused at our tactic, until we had cast about 20-30 spells on every grouping of attackers, and, with great smirks on our faces, reminded our DM that Haste ages the recipients 1 year... and seeing as the Knights were human, the DM had no choice but to admit that his grand army had not attempted to save against the spells since they were beneficial, so we had bypassed their magic resistance, and they were all slowly turning into fumbling, senile old coots who couldn't hold onto the ladders anymore due to arthritus and were too weak to push the battering ram anymore (and they thought they were moving faster cause of adrenneline hehe). Within about 10-12 rounds, with every mage casting haste every round, we were able to walk outside and literally dance on our legion of enemies. After that we decided to start new characters to make the DM happy, but we still regularly visit our old characters and talk about how great it was when we killed the Black Knights, as our new characters were... mages, who apprenticed under our old characters. hehe HURRAY FOR RULE EXPLOITING!
The second best moment involved a mage, a werewolf, the punching chart in the Players Handbook, and a lucky arse roll on the knockout %... and yes, another happy dance on my helpless victim
I'll spare everyone the long version of that one, cause as you can tell, I talk too much.