Sometimes the simplest games and activities are the best. Why not have a Teddy Bear's Picnic, all you'll need to do is set up a picnic blanket with a plastic tea set. Maybe add some real food, especially if you have fussy eaters because turning eating into a fun activity can often help. Let them bring their selected fluffy guests and you're all set.
After lunch why not take a stroll around the garden, turn it into a Nature Treasure Hunt by making a list of things to find such as a birds feather or a flower. Separate into teams and race to collect them all!
Get back to nature on a Sensory Trail by wanding around the garden with your child touch the grass, smell the flowers and ask them to discribe the way they feel, soft or rough and their scent sweet, stinky or lovely and fresh. This will help their senses and allow them to learn more about nature.