Save the round metal lids from tubes of frozen juice. When you have a couple dozen, turn them into a memory game. Choose two photographs each of twelve familiar people and pets, cut them to fit inside the juice lid and paste in place. Or use twelve distinct fabrics for a pattern match. For older children, put a written number one through 12 on half the lids and corresponding number of dots on the other half. Turn all the lids upside down and let your child turn two over at a time in an attempt to match them.
Save cardboard tubes for a marble run race. Cut the tubes into chutes by removing the top third lengthwise. Hot glue strong magnets on the back. Arrange them into two twisting and turning tracks on your refrigerator or other metallic surface and put boxes at the end. Have your children drop a marble into the top chute and see whose reaches the box first.
Collect vintage clothes, pieces of costumes, wigs, jewelry and other dress-up accouterments into a chest. On a rainy day, pull the chest out and let your kids have a contest to see who can come up with the craziest, the prettiest or the best super hero. Continue the game by encouraging them to make up stories and act them out for an audience of parents, grandparents and older siblings.
Ask your local carpet store if you can have or buy some samples. Use the squares to build a life-sized board game. Wrap squares around a box with white or brown paper for a dice. Use a bingo dauber to make the dots. Designate some squares as pick-a-card spots and make up big cards with instructions like hop backward three spots or spin forward three. Some cards can just have silly tasks, like make your favorite animal sound or make a funny face.