If only you could freeze lettuce or bananas...
Don't know about freezing lettuce, but you can certainly freeze bananas. When ripe, simply peel them, put 'em in a freezer bag and in they go. I don't know how long they will keep like that, but I've never had one go bad. No, you probably don't want to pull one out and eat it like you would a regular banana, but there are many things you can do with it. For example, add a frozen 'nana to a cup of milk and blend for about 20 seconds. You'll have an instant frothy banana milkshake that is delicious and nutritious. I have one about every morning with protein powder, and sometimes add some other fruit too, like some berries of some sort. Frozen bananas can also be used in baking, such as making banana bread. You might want to use the ripest ones for that. Just try the shake. You'll be amazed at how good it tastes.