We recently had a kitten in our care for 4 weeks and unfortunately that's just how kittens are I'm afraid!
Kona, the siamese kitten we cared for now lives with my mum and we had the same problem with him. He would play and play and play all night and it was a huge effort to get him to sleep. I would lie in bed at night having to go to the toilet but trying to hold it because I knew if I got up he would spring back into action!
Hissy's right, they do grow out of it - eventually.
Because we both work full time he didn't have anyone to entertain him during the day. On the weekends we would take Kona outside to play with us and we'd really wear him out - by the time we went to bed he was ready to sleep the whole night through! We loved the weekends because we knew it meant a good nights sleep for all!
Your kitties are at the same age Kona was when he began sleeping the whole night through so make sure they've got heaps of toys to play with and invest in some quality play time and you should be rewarded with a good nights sleep!