I do like the idea but I also agree with Fire Hawk that there are already so many daily/weekly things to do for a rs player.
Maybe make it a montly thing with a highscore for clans aswell and reward the top 10 clans with citadel boosters/double ava xp boost/...
Ceecs - leader of Ceecs Clan
Rank in Star Find, Harmed Ore, Beach FC | Ex-Rank in Fast SC
Ceecs Clan: DUTCH ONLY RS3 clan & Winner of the Iron Skilled Cup 2015!