Cycling off road in the dark, I recommend using good lights though, you'll be concentrating so hard everything else in the world will go away.
Climbing, when on the wall and climbing well I'm so focused it's just me and the wall nothing else.
I use my mp3 player, a lot, first thing I do every morning is put my earphones in.
Reading sometimes works, I can't always just sit and read though so find short stories work better for me.
YouTube, I spend far too much time on YouTube, but is good for discovering new bands through the recommended videos.