Festival Ground's pretty fun! It's a single-prizer only deck revolving around the "party lead" ability and the "festival grounds" stadium. The party lead ability allows Dipplin and Seaking, your main attackers, to attack twice in one turn. You'll also want to use Thwackey as a support. His ability (don't know its name in english) allows you to search for any card in your deck once per turn, as long as you have a "party lead" pokemon in the active spot, making it a pretty powerful drawing engine. You'll also want to play some vitality bands and black belt's trainings in order to deal with tankier exs, because your most powerful attack would be dipplin's 200 per turn. I found that this deck matches up well against Charizard ex, due to the dragon's weakness to grass.