I have no idea. When I had DH's golden birthday last summer I put on the bottom of the invites "kids welcome", some of our friends brought kids, some didn't, but our kids were here, so I figured our friends may as well bring theirs too. Not sure how to say adults only.
Re: Adult birthday party invite question
"adults only."
"Leave the kids with a sitter and get ready to have a good time."
"Get a sitter, put the kids to bed and come on over."