What can I do about the neighbour's kids climbing over the garden all the time?

Put up some barbed wire.

First of all stop your own kids. A full week of being confined with no tv or computer should do it. If your kids don't climb the neighbors kids may not either. Second, talk to the neighbors Mom and have her agree that her kids are not allowed on your wall. If they are call the police, for trespassing. 3. Put spikes on top of the wall, this will make for uneven footing. However, as I'm sure your aware, the kids can fall and get hurt and guess who is going to have to pick up the bill.

You are adult and they are children. The sensible thing to do would be to be friends with the neighbours. Talk with the parents - no yelling - tell them your worries about the dog possibly nipping the children. Then offer to, and if accepted, put a gate in the fence so the children can get their ball without breaking the fence. Regarding your right to privacy if you explain to your neighbour that you are passionate and spontaneous but if the children intrude they may see what they ought not to.

Having done this remember the children are children and do not really mean to be nasty they just think my ball is in next door's garden I will get it. Be nice to them and they will respect you

Since its your garden; I think you should get the police involved because technically they're trespassing. You can have a cop or two turn up and let them have a word with the kids. Also you should tell the officers that its for their safety anyway as you have a dog and you don't want to put your dog down for attacking the children when it's their fault for going into the garden. If their mum turns up and gets mad at you for reporting her kids then just tell her she had her chance to control them.

I'm sure this may have come to your mind, but how about telling their mother about how you feel. If she is kind then explain and she should do something about it, maybe even tell them to fix your fence (if you are lucky!). If she does nothing then maybe consider going to the police. Yes it may seem a little extreme, but, its actually a mild form of breaking and entering. If you think about it, they are breaking into your garden then looking into your house which is disrupting your privacy. Obviously don't ask them to arrest the kids, but you could get them to go to their house and sit the children down and talk to them...

Yeh , I agree with other answers. Either keep or pop their ball, but also put some sticky stuff along the top of the fence. Something messy.

Paint some sticky tar like substance on the top of the fence.

You will have to erect a bigger fence or put up with the intrusion.

When the ball lands into your garden take it and pop it,

barbed wire fencing !!