Mine fun moment was also about beholders.
Spoilerish, I might say...
When I hit the beholder lair, I had the cloak of mirroring on. So I ran through all the lair, lured all the eyes (including the elder one

and some gauth) into a big room, then simply stood in the centre and ignited a cigarette

after the half of that stinking goo was burnt into ashes, all I got was 10-15 beholderish statues around me. Looked like a beholder history museum - here you see some gauth, here they are grown up so they became beholders, and here is their leader, The Elder Orb, ladies and gentlemen! Ah, I also forgot to mention (rather essential) that I got no damage at all, and the XP made my Minsc and Keldorn level up a bit