[pegasus]

Doing nothing does that for me. Seriously. I'm regularly confronted with this feeling, and one thing I found over the years to consistently lift me out of that trough of meaninglessness is meditation. It boils down to "if nothing seems to matter, then just don't do anything". But I have to resist the temptation to just engage in some form of escapism and just sit there with that boredom. Initially it's hard, but after about half an hour to an hour the feeling of boredom and meaninglessness recedes, and my mind becomes more calm, focused and purposeful. It's as simple as that, at least for me.