What would you do, close friends kids are a bit of a nightmare, rude, ignorant and spend most of the time shouting or making stupid noises. Come round every morning before school and most afternoons after school (not for very long) which can't be changed but becoming a real frustration. You know when you want to tell the parent's that they really need to sort them out but that would really offend
Children shouting and making stupid noises seems fairly reasonable behaviour to me. If they are ignorant and rude then look to the parents - and actually it's your house and I remember when I was growing up that if you didn't say please or thank you then you didn't get what you asked for, and my mum was perfectly capable of getting us and all the multiple children she looked after to behave in a reasonable manner without losing her rag.
I have a rule in my house, any child has to live under the same rules that my kids do, if they don't they get roared at as my kids would if they step out of line. Tell them firmly to behave or they won't be welcome.