We use vinegar to clean and then reuse the 4L jug it comes in to chill water in the fridge. I keep 2 in the fridge at all times - we drink a lot of water - and one in the freezer to use in our cooler. I replace them with a new one when we go through a new bottle of vinegar and recycle the old ones.
All the plastic containers from yogurt, cottage cheese, margarine etc. I use to freeze our soups, stews, sauces and shredded cheese. We also use them for leftovers.
Large ice cream tubs get reused all over the house: food storage for bulk purchases (flour, rice, beans, etc.), popcorn tubs, taking salad to a friend's for dinner (I don't worry about losing the dish that way), cleaning buckets and storage for cleaning rags.
When we shop online I keep a few sturdy small boxes to ship gifts to people at Christmas.
Plastic grocery bags are rare here - we bring 2 rubermaid type containers with us to the grocery store and put all our groceries in that. The bags we do get from stores get reused as small garbage bin liners. If they only have dry items in them then I just dump them into the big bag and reuse the bag as long as possible.
Produce bags get used as kitty litter scoop bags. 3 cats = a lot of scooping.
I'm short but I keep all my plastic containers up high on my shelves. I kept a few sturdy boxes and looped a strong ribbon through as a handle which is just within my reach. When I want the containers I grab the handle and pull the box down. I hate having to use a stepstool. LOL
Our eggs come in clear plastic containers so I use the egg cups as paint trays when I'm doing crafts. (Washable non-toxic paint so they can still be recycled.)
Right now I'm trying to figure out what to do with a bunch of tiny glass jars I got for Christmas. They were little jam samplers and they're so cute I don't want to recycle them. I thought I could reuse them as bath salt containers for gift baskets or to mix my paints in so I can have a few pre-mixed colours. Anyone have any other ideas for them?