I have leftover sourdough-ish baguette!!
The 90's version of the Joy of Cooking has a very decadent chocolate bread pudding recipe and I have used both challah and sourdough successfully.
You could also let it dry and then whir it in the food processor for homemade breadcrumbs to keep in the freezer.
You could also make a strata, with eggs and vegetables, like a frittata, except with bread.
I save ends of bread and slices of any kind of bread, that would go stale or mouldy, before I was to use it, by drying out out and using it as a crouton on salads, or in soup. I have several pieces right now, saved in the freezer...some are sourdough, some multi-grain..
It's just another option...