Upcycling: A More Compact "Carrier" for Cotton Crochet Thread

What can you do with those empty toilet paper tubes when you're done with a roll?  This is what I've done.

I fold the tube in half, and then in half again.  Then I put the free end of the cotton thread into the fold and just wind the thread onto the tube.  The result is small enough to place in a crochet hook case and carry anywhere.

As for the cotton thread tubes, those could be turned into something else too.  I'm thinking of a desk organizer using three or four of these at different heights.