Tyga's Son King Cairo -- My Birthday Party Rules, Bitches!!!

Tyga threw a birthday bash for King Cairo Friday, and every kid who was anybody in Hollywood showed up.

The Racer's Edge in Burbank looked like a Hollywood toddler nightclub ... Kanye showed up with North, Chris Brown was there with Royalty in tow, Travis Barker and his brood were on hand, as were Kourtney Kardashian and her kiddies.

Blac Chyna -- who was not present -- is throwing her own party today.

Indoor go carting is a tough one to beat.