Look what you can see in next week's Naruto episode preview:
Will it show something about Sasori's past? Who knows! But it'd be cool! ^^
Next Episode #319 will be called "The Soul Living Inside the Puppet".
Btw the mystery of Sasori's headband seems to be solved. He used to wear it on his forehead. The question now is where he used to wear it when he joined akatsuki (if he took it with himself).I found young Sasori so cute in that screenshot