Other than, Centara Grand, Hard Rock, Pattaya Water Park, Planet Football and Splashdown, any ideas for a kid's birthday party venue to accommodate approximately 20 kids?

Pattaya Sheep Farm

A day at Nong Nooch Gardens.

Crocodile farm?

Tiger sanctuary?

or if you are feeling a little more risk averse, Elephant tour.

McDonalds

I should have mentioned that the kids are from 9-10 years of age and are very active, thus the replies received to date, although appreciated, will just not do.

I may opt for Planet Football on SSCC.

http://www.splashdownwaterparkpattaya.com/#!page4/cfvg

if the kids are over 120cm in height, they might love this place. Been past it a few times and looks like a right laugh.

Go kart?

I suggest you stay away from Spalshdown as I had a very bad experience there. There are no safety instructions, the staff are Cambodian and therefore do not speak Thai/English, and when I jumped off one of the elevated platforms onto a ball I ended up under the platform in very dirty water and had no idea where the way out to the surface was. I kept hitting the platform every time I tried to surface, after approximately 30 seconds of panic I gave it one last chance, after saying goodbye to my daughter, and was extremely fortunate to grasp air rather than the platform. When I scrambled to the side and exited from the water the staff just stared at me and offered no assistance whatsoever.

My daughter had been screaming for help when she realized I was in trouble but nobody came to help.

The expatriate owner gave me back my money but offered little/no sympathy and proceeded to inform me that the place was safe. <deleted>.

I suggested that a qualified swimmer be present in each of the pools to offer assistance and that not more than one person be in the pool at the same time, safety instructions provided and Thai/English speaking staff were present at each pool - this was/has been ignored.

When I mentioned this to a few colleagues I was not surprised to hear that people have also cheated death and experienced many other minor injuries e.g. broken fingers.

Safety comes first, not here, it's all about the money.