How come time flies when your having fun?
The quick and dirty answer has to do with the way your eyes, ears and other sensory organs input information into our brains. I read a really interesting article about it the other day if you are interested, here is a link http://blog.bufferapp.com/the-science-of-time-perception-how-to-make-your-days-longer
Because when you're bored you usually pay more attention to the time and when you're having fun you lose track of time.
because that's the time when you're not paying attention to the time
When you're having fun, your brain loses track of time, and doesn't focus anymore. :)