Had something similar happen to me recently too. One of my friends (a 6-7) from school a couple of years ago added me on MSN earlier this year and is nearly always the one to open a convo. The convo basically died pretty quickly, so after a few minutes of silence it went something like this:
Me: "Entertain me."
Her: "No, you entertain me!"
Me: "Pfft, what are you so busy with, anyway?
Her: "Nothing much, really...just chillin"
Me: "...You're watching porn, aren't you?"
At least kept the convo moving a bit
