1) Castle wars, without any doubt - played multiple games a day before I got muted, and quit 2 years ago. I still have the 1432 tickets I earned such a long time ago, they just sit in my f2p bank with my fighter torso and a fire cape now. 2) Clan wars, since I have now returned and don't plan on getting my membership back until i'm sure I don't get bored again. People tend to get a little bit too serious in there though, and it's one big backstabbing-fest in the busy worlds. KO'ing people in red portal is also great fun, it barely ever works, but when it does, I always laugh my [wagon] off irl. 3) Fist of Guthix - I know it's noobish and requires little or no skill, but on my second account I get to win most games and it also gives me some profit, which is not the case in any of the above.