Haha! It's always funny when that happens. I was doing an internal presentation to my colleagues and bosses, I took some screenshots without realising I had my Google Play Music tab open, was listening to the Butthole Surfers. Had some interesting questions from the MD at the end...
Could have been worse, this recent news story made me smile:
http://news.sky.com/story/1697663/candidate-left-porn-tabs-open-in-facebook-post
You couldn't make it up !