What is a "Golden Apple Hunt-esque" mission for me to undertake?

I've found Minecraft is only fun when you make it fun. For me, this is assigning goals for myself and setting out to do them. But now, I can't seem to find enough goals to do. I'm sure many of you have seen "Hunt for the Golden Apple" series on youtube, and I was wondering if any of you guys had "long standing quests" like this that I can undertake.

Winning the game is not exactly something I'd like to do (doesn't seem very much fun to me). And obviously I'm looking for something other then finding/making a Golden Apple.

Looking forward to see your ideas!