You can learn anything in 20 hours: What do want to learn?
So to attain a decent level in anything, you need to spend 20 hours(see the TED conference). You are not going to be a master, to be clear. This requires countless hours of dedication. But do you need to be a master at everything?
Dance, sing, play,...
...write, cook, draw... It just doesn't matter. I want to learn guitar, but I won't start a band.
I want to draw, to explain myself easier, to envision my stories in another way, not to expose my drawings.
I want to be cool on a skateboard, not doing backflips, although ...
You won't make World of Warcraft, maybe not even Pacman or Pong. But you will enjoy the ride, learn in the process..
And have the skills to have fun.
So what is it you want to learn... There is 19hours 59 minutes and 57 seconds left ^^