Many of us, I am sure, have had characters whose stats would make even certain ToB NPCs sigh in vain for, whose level progression and proficiencies were planned out millions of EXP in advance, and would dual wield the +5 Givers of Most Plusses.
Which can be fun (and certainly WAS fun for me on my second full runthrough.)
But sometimes a character concept (and the self imposed difficulties) can be just as fun.
For me, It would have to have been Ogg The Barbaryn. Yes that was his name.

Yes, that's how it was spelled.

His stats were
19 str
16 dex
19 con
1 int (

)
14 wis
18 cha
He dual wielded war hammers. Why? Because he could. It was pretty much all he could do. He looked rather impressive, whacking away with a two 40-odd pound hunks of metal. Sure, the BASE damage wasn't much, but that didn't stop Ogg. He would also go through pretty much a temple's worth of Genius potions every time there was the least hint of an illithid nearby.

Ogg had to be led around by the more astute members of the party. Like Minsc.
I also once made a female elven Kensai using the "Default 2" soundset. I would have made her Chaotic Neutral if I could. The whole point was to make a Kensai using a race least suited to unarmored fighting (a Con penalty, no dual classing possible.) She was a fun character, but she was an early character, and I couldn't figure out how to keep her from taking 50 or so points of damage per goblin. (She was an early character.)
And one final one...
When I first installed ToB, I wanted to take a look at the expansion, even though I was only in Chapter 2 of SoA. So I spend a good half hour making a Mage/Thief, hemming and hawing over placing points in thief skills I didn't fully understand how to use, selecting spells I had never used, etc.
I got killed in the first fight.

Without saving

.
Anyone else? Let's hear about some of your FUNNEST characters, no matter their power level.