My next door neighbor was using a heavy duty turf roller to roll his yard and ......?

He broke it, so he is responsible unless you decide to handle it yourself.

If I had a good relationship with my neighbor and he accidentally damaged something, I would probably cover the cost to preserve the relationship.

He broke it, he fixes it. Simple. Be nice about it, though.

Was he having sex with it. You do not tell us what he did.

Insurance, I assume he was doing this as a favor for you and if so then David S has a good answer.

As you knew what he was doing you acquiesced. Therefor it's your problem not his as you approved his actions.

My next door neighbor was using a heavy duty turf roller to roll his yard and decided to roll our yard too. It looked like a piece of farm equipment where you sit inside a cab. Anyway he got a little too close to our house and took out our 2nd floor gutter.

Who would be responsible for replacement is my question?? Thanks.