I don't really remember who introduced me to this but I remember being out in the parking lot of my high school late one night and I looked at the clock and it was 11:11. When I mentioned this to a friend who was with me they told me to make a wish. I have since adopted the 11:11 wish tradition and since I just made an 11:11 wish I decided I should try and spread the tradition.
The rules of the 11:11 wish are these 1) you must have randomly glanced at the time and discovered that it is 11:11 you cannot contrive to see the time in order to make the wish. 2) The 11:11 wish can only be made at night if it is 11:11 in the morning it doesn't count (of course you could argue that really then it should be the 23:11 wish but that doesn't sound as cool now does it?). 3) The wish must be made before the time changes to 11:12.
If you choose to adopt the 11:11 wish feel free to modify the rules as you like but these are the rules I adhere to.