To create a giant jigsaw puzzle, place nine large envelopes together, in order to make a canvas. Use pieces of tape or paper clips on the borders to keep the envelopes together, and then make a drawing across the whole surface. Separate the envelopes, which are the pieces of your jigsaw puzzle. Mix them up and assemble them to form the drawing. Make a memory game by collecting pairs of identical pictures and putting one into each envelope. Alternatively, cut small squares from an envelope, draw symbols, letters or numbers on them and organize your memory game.
Transform a large envelope into a head mask by cutting holes for the eyes and nose. Paint with your favorite colors, glue on leftover fabric or colorful paper and use yarns to make the eyebrows, hair and even a mustache. Stuff the envelope with old newspaper to make the body of you puppet. Use stacked yo-yos (round pieces of fabric gathered in the middle) to make the legs and arms. Stuff an old sock to make your puppet's head.
Recycle leftover envelopes into gift bags to give your friends. You can decorate them with pictures of your friends or pieces of paper of their favorite colors. Make it a luxurious gift bag by covering it with foil paper, sequins and pieces of ribbon. If your friend likes to travel, glue pieces of old maps and postcards on the envelope. Decorate a Christmas gift envelope with old Christmas cards and felt Christmas decorations. For Valentine's Day, redesign the envelope by cutting off its edges to create a heart-like shape and then glue the new edges.
Make a multiple aperture photo frame by drawing stars, hearts, flowers or simply squares or circles on one side of the envelope. Cut the shapes out and tape the picture inside the envelope. Decorate your frame with small sea shells, ribbons, cork pieces or beads. Glue a piece of cardboard on the back side of the envelope to add support. Another idea is to draw a single large shape on the envelope, cut it out and put a single picture the size of the envelope inside.