Any magnezone variant usually are pretty fun to me, especially using ERL to take 5 prizes. lol, other than that. I like Mothim, Palkia/Lucario COL, Steelix prime.
It's all about the Rampardos Donk! XP 1 fighting for 80 Damage? Awwwwww Yeeeaaaaahhhhhh
or eeveelution deck insanity ftw which i actually went 4-2 at cities with. (5-1 without my terrible misplay)
My favorite deck is my Dusknoir X / abamasnow spread deck... spread decks are always great fun ... taking six prizes with one blow is always fun... don't know how really viable it is... I will also PM you a deck idea which is super fun to play for me that I kinda want to keep secret : )
RYCHOMP!!!!
you start out with garchomp lv x and snipe the bench for prize cards then use Ryperior Lv X to as mortal kombat says "FINISH HIM!!!" it has destroyed lux chomp many times this guy at my legaue built one identical to the world champions deck and after loosing to RyChomp 5 times he doesnt use it anymore its fun having unlimited power! Ryperior Lv.X is an ANIMAl! dont know what he does google him!!!! lol
It all depends on what you consider fun I guess...I love Regigigas and consider it a blast to play (lol I'm a giant unstoppable basic, just try and stop me everything not named Machamp), but yeah...all depends on the person imo.
Hm...
I did have some success once with a Nidoking/Nidoqueen deck. Though one deck I've pretty much never seen is a Metagross deck... it's like nobody likes the big guy either:
A. switching the opponent's Pokemon
B. Making K.O.s easier
C. giving a whole psychic deck free retreat
or
D. just plain kicking butt with Quad Grand Smash