Q. Can bananas be frozen?
Sure they can. I do it all the time, for use in breakfast smoothies.
Just remove the peel and drop them in a resealable freezer bag. If you're going to eventually puree them, it helps to cut them into chunks first.
You also can refrigerate bananas, to keep them from getting overripe so quickly. In that case, leave the skins on. The skin will turn dark, but the banana inside will be fine.
Q. What's the shelf life for a package of hot dogs, and how can you tell when they've gone bad?
An unopened package of hot dogs should keep in the refrigerator at least two weeks; an opened package should keep about a week. They can be frozen for longer.
But those are approximate suggestions, of course. How long they'll keep also depends on whether they were handled properly (you didn't leave them sitting out on the picnic table for an hour after your last cookout, for instance) and are stored at 40 degrees or less.
They shouldn't smell bad, show discoloration or have a slimy texture.