Slice them VERY thin & toast them to use as bagel chips. Or you can also slice thinly, brush with olive oil or butter & season with garlic & bake in the oven for flavored bagel chips. Be careful slicing them if you don't have a bagel cutter.

Here are some more ideas.

Here is a link that might be useful: Bagels

I would put some sauce and some cheese on them, bake them and make pizza bagels!

Microwave them wrapped in a damp paper towel to soften it up.

Day old bagals are just beginning to get good....toast them gently and spread with cream cheese.
Split and freeze the rest and take them out and toast them while they are still frozen.
Linda C

Another use for leftover bagels, or any bread, is to rip them into smallish pieces and grind them fine in a blender or food processor for bread crumbs. Put them in an airtight container or zipper bag and keep them in the freezer. I use them right out of the freezer; just crumble them with your hands if they clump together.

Once I checked the saturated fat content, not to mention the additives and cost, of packaged bread crumbs, I never bought them again. I think the homemade ones taste better, too.

I also make home made bread crumbs out of stale bread...but I don't consider day old bagels stale ! LOL!
After I grind the stale bread I spread the crumbs on a cookie sheet and toast them in a 250 oven until they are golden brown. Then, If I am really ambitious, I separate into little baggies and add garlic salt, dried oregano, basil and some ground red peppers....and into another dry parsley and parmesan cheese....and cinnamon and turbanado sugar in another for topping pudding, flans and lining a cake pan.
Linda C

My favorite breadcrumbs are made with English Muffin Bread-I make two loaves of it and chop one loaf at a time up in the food processor and then freeze them as gellchom does.

Make your own stovetop dressing. Peel off bagel "skin" with sharp knife or whatever. Pull apart remaining bagel in small, roughly one-inchish pieces. Can leave out to get stale until you accumulate 4 to 8 cups. Sautee a couple tablespoons chopped celery with tops, slivered onions, and some minced fresh Italian parsley in butter in heavy Le Crueset type pan or whatever you have 'til celery and onions are soft. Sprinkle with poultery seasoning (Spice Islands is nice) or thyme and a smidge of sage, salt and pepper to taste. Sautee a handful of the crumbs in this butter mixture to lightly toast. Transfer to small pot or saucepan or whatever you have. Add remaining crumbs/bread pieces. Add one half or more cup homemade chicken stock or whatever canned variety you have or prefer, bring to boil, cover and turn to low heat for five minutes. Turn off heat and let set another five minuts. Add less or more stock depending on how wet or dry you like your stuffing/dressing. If you need specific quantities, let me know. You can mix in other leftover bread, cracker crumbs, etc., and it always works.