I was reading a really good book recently called redeeming love by Francine Rivers (brilliant book, one of the best books I have ever read.)
Well in the book one of Angel's friends shows her a prayer box that she has made from an old hat box. She has basically cut a slot in the top and whenever she has something she needs to pray for she just write it down on a piece of paper and drops it inside.
Then ever so often she'll open the box go through select a few at random and if God as answered her prayer she removes it from the box.
When reading the book this really hit me as a great idea, especially because when you were feeling low you would be able to go to the box, and by looking at the prayers and seeing how many had been answered by God, help yourself to feel a little better, and also help remind yourself that God answers all your prayers eventually, maybe not in the way you hoped, but in the way that is right, and that would help you to pray to God with your current problems and be able to feel certain again that God loves you and is watching over you.
So I will be starting my own prayer box as soon as my new, very pink and very cute hat box arrives I can't wait.
Really I think you could use all kinds of boxes for this, perhaps even a cute bag or something like that, what ever you use I think it is a great way to pray.