Your question got me thinking letterme, so I stopped what I was doing (nothing) and counted the number of hubs I have in my 'hub draft' folder - 58. Not only that, a few of these drafts will expand into dozens and dozens of hubs. Do what leroy64 suggests - lately I have taken to keeping a few post-it notes and a pencil beside me when I'm watching TV. The ideas waft through your mind so quickly that it is imperative to jot them down.
mbyL and starstream have the right ideas as well. Take notes regarding your hobbies and remember that although you may think your daily life is boring, millions of people may consider it fascinating.