If somebody asked me the same question, I would quickly reply, without a doubt, something that gets me going, may be a song?
However, sadly, Not all boredoms are same, nor is every person. Sometimes you get bored because you have emptiness of emotions — like a picture without colors, or Sometimes you're bored because your loneliness is killing you — like a dark night without moon and stars.
That's not all but in some cases you're happy yet you're bored. You can't find a reason what's bringing the indifference inside you.
It's not at all necessary that you'd want to find something to overcome the boredom. It can be anything, from beholding a nice old picture of your loved one to watching a full length movie with humour. It may be doing a little bit of your favourite work to reading a passage of motivation. It can be a little hug, a shrug, a shower, a walk, a moment of self realisation in front of a mirror or can be anything. The options are unlimited.
In my case, it has always been writing about what I want to let my mind think in the moment and write them down. I got a little bored today and thought I should write it down on @sn. This always worked for me and it is definitely working today. Within a few minutes my draught of emptiness is filled with rain of interest. Whoa! I am feeling great again.