I remember going places as a child with my 'busy bag'. Mum put together a bag for myself and my sister that contained a little doll, pencils and paper, a puzzle, and I forget what else. We loved playing with them: on holidays, at people's houses, at church. Sometimes we'd ask Mum to get them out for us to play with at home.
I filled them with notebooks, puzzle/colouring books, stickers, a new book [picture book or novel], a few coloured pencils, a lead pencil and rubber. They were a hit. I whipped up four over two evenings, no sweat. And the best part is, they can be used over and over at church, when waiting in the car, other holidays.
I will post a tutorial soon. I'm thinking I may need my own, it's just the right size to fit in my bag, and better than any organiser I've ever owned. You could customize it with pockets etc. to suit your own needs.