My best tip I ever got (first as a substitute Bnos leader, then as a camp counselor for far too many years) is that, if you have elementary school aged kids, you should do an activity with them THAT THEY DO NOT YET KNOW. Teach them something new and cool. This will hold their attention.
Do they all have to be together? See if you can divide at all.
Maybe try a full-motion game like Coke and Pepsi (I did it with kids and we kept on making up new rules- it was a lot of fun and took up a lot of time 🙂 ). Remember, your object here is to take up time.
This seems like a Tisha B’av camp- if not (or if the kids are young enough and you don’t mind) food decorating can be great. If you have little kids, the weirdest tip I got was to make smoothies with them. And it worked- they loved watching the blender go and all loved drinking them after.
My one and only Tisha B’av camp, the kids decorated hats. And picture frames. And pictures for the frames. You can’t go wrong. Someone will always finish in five seconds, so you tell them that it looks gorgeous and make them feel like an artist and then shove another paper in their face and tell them to make another one to hang up on their wall.
If they’re young enough, they might like the Morah Music type tapes. You won’t, though. They get stuck in your head like you wouldn’t believe. I still know the Hokey Pokey in three languages.
For older kids, Freeze and Justify, Charades or some other kind of acting game can be fun.
Good luck!