Hidden in Stranglethorn Vale is one from "for fun" quest included in World of Wacraft. Cortello's Riddle is tiny scroll hiding on few spawn spots inside one from three pirate chips. So, if I may suggest, while doing the quest for three captains, go one step (actually floor) further deep in that ship and find Cortello's Riddle. I can promise that this quest will take you into three interesting places. The quest itself start at lvl 35, but surely you will keep doing it up to your forties. I won't disclose where it takes you and how to find pieces of this riddle as it would loose the fun part of discovering (and anyway, you can find it on Thottbot if you are too lazy). On the end of 3 steps quest chain there is Explorer's Knapsack (14 slot) and lot of XP waiting. Enjoy