Oh my god i HATE when this happens! I was having a nap a while ago and a mate dropped in with her dh and his friend.. they were all drinking.. i was so annoyed that i cldnt even pretend to be happy to see them!
I think its just so rude.. its like they are saying 'we are more important then anything u are doing therefore u will drop everything and entertain us!'
If ur dh doesnt mind seeing them maybe when they turn up just continue to do what u were already doing or yeah just go and do something else! Surely they will get the hint eventually!