I find myself sitting around checking sports scores, looking up hobby-related things, putting off work, and discovering new TV shows to watch in their entirety far too often. Especially because the entire time I'm doing this, my mind is saying 'I want to write something amazing!'
But if I actually opened up Microsoft Word and tried to translate whatever idea happened to be floating around in my head onto the screen, it wouldn't happen. Writer's block isn't something that can be 'poof'd' away. I find that when I get an idea like that, say "A man takes a trip across the country without any guidance or thought and just observes the landscape" that I can't really just write it. But if I map it out, figure out what I want the story to say, how the man acts, what his favorite flavor of ice cream is, then I really want to write about him.
My advice is: Take the idea you're working with and try to map it out. Don't write coherently if you can. Fragments are better or you'll feel like you're writing and the 'block' will creep back in. If you're used to typing, grab a notebook and a pencil and jot some notes down while you watch the news or a mindless show like Jeopardy or something. If you're still having trouble, I've also found that doing an intense editing session puts me in the mood to continue a story. The mindset that, "Now that I've polished up the first twenty pages, I can finally move on to the next twenty."