- Go into the archives of your LJ.
- Find your 42nd entry ever. Yes, this may require some counting and basic math. Deal with it.
- Link to that entry in a new entry. This is the meaning of your life.
Well, if I'm counting correctly, the 42nd entry in my LJ is my coming back from the church canoe trip three years ago. I don't know that the church canoe trip is quite the "meaning of my life", but I'll agree that it's been pretty important the last few years. (After all, I probably wouldn't be singing in the church choir had it not been for the first canoe trip.)
 Usually, I credit those from whom I get these memes. In this case, however, I've only seen this in friends-locked entries, so I'll allow the individual(s) to remain anonymous. Besides, they know who they are ...