Ignoring all the other comments, this is seriously one of the most addicting things (not just games) that I have ever done. I seriously recommend that you never start playing. Recently a kid sued JaGex for $5000 because he didn't go to school or anything, he just played this game. Seriously from someone who is actually addicted to this game and has been for over 2 years: DON'T PLAY THIS GAME!
The most addictive game ever created, its gotta use subliminals