Like Gawqueenpenguin and Rhayne already said bring somethings with you for the between times. In the begining though try doing some physical things, like hide and seek, rock,paper,scissors, and maybe dancing.
After words pick out a movie, and just have a bit of quiet time.

Just remember to be firm when you need to be, or they won't behave for very long.
When it comes to getting them to go to sleep, see if you can get them to make a promise or try to make a deal with them. If they don't go through with their end of the promise then you tell them that it's not nice or good to break promises, and work from there.

Just so you know that dosn't always work but it can help.

So really just get rid of their energy, so that it will make it simpler to get them to go to sleep.
While making sure that they have a good time as well.


I hope that helps.(works for me when I babysit the neighbors kids, and I keep getting asked back)