Stuck in a rut

Why is it that when I want to create a new piece of work I hit a brick wall? Not literally, you understand. It's that white piece of paper. It sits there staring at me threateningly until I put the first mark down. Unfortunately it has been so long since I have done any serious art that I can't even make that first mark with my pen. I am contemplating making my first big collage to try and inspire my artistry to come hither. But I am being threatened by another piece of white paper there too. Maybe I should switch to painting on another colour of paper.