I was fixing a couple of minor bugs in a program I've been working on, when I made the mistake of typing cout<<string('\n', 1); instead of cout<<string(1,'\n');
I didn't get any compile errors and the programs reaction gave me a bit of a laugh. Instead of the blank line I wanted to put in, I got :):):):):):):):):):) (10 of them). It just made me wonder as a relative C++ beginner what other "easter eggs" are there that people might feel like sharing.
edit: aww, shame this forum doesn't support emoticons.