I always take my sketchbook around with me and currently my sketchbook of choice is a brown paged A5 number. Drawing on coloured paper makes thinks interesting aanyway but this past few weeks I have been having lots of fun with liquid paper/ white out/ tippex unlike some paints it leaves quite a smooth surface and doesn't distort the colour of the inks or biros in my case!!
try it out and see what you think!!