Is it ever OK to lie about your name? What 'alternative names' are the most fun to use? When are the best times to give a fake name?

I say, that its fun to bring back the old childish gag of lying about your name.
I do it regularly in the following circumstances, and only disclose my real name if I feel that I might actually stay in touch with this person. No joke, I met my ex-girlfriend by first introducing myself with an alias. It was only recently that I remembered how much fun it is to not take a casual interaction seriously!
I promise you if you introduce yourself as something/unique 'crazy' like "Morpheus" you will have someone's attention! Yes at first they will suspect you are either crazy or f*#king with them. But if you can 1) hold a straight face and 2) justify a legitimate reason for the name, you will totally have their attention!

Best times to give a fake name: 1. On planes, especially if you think the girl/guy is hot! Seriously think about it, most people are 'Pavloved' to think that seatmates on planes can be a pain the ass, especially if they are both talkative and boring. Some people I know even wear earphones just to discourage someone from talking with them on a plane. But use a play name, I promise they won't tune you out so quickly! They will at the least hold off till they see what you are about. Another helpful hint, don't call yourself something outlandish like "Morpheus" but then tell them you are an accountant. :)
2. *At a club or bar! Remember those places are about having fun, not taking yourself seriously!
3. When you know the chances of running into this person again are less than .001%.
Any other thoughts?