If you want good all you can eat grub at reasonable price Cosmo is good. If you're looking for something a bit more intimate (and expensive) the Pearl of the Orient is good.
Ok, going there on 17th for my b'day whoever wants to come along.(Cosmo)
Bowling to entertain kids first then go karting, then food.
Edit- maybe karting first......bound to have a few beers while kids are bowling. http://www.team-sport.co.uk/cardiff/?gclid=CPi6mKD1lqsCFQcntAodVQP5tA