Turn a metal tray into a message board. Paint one side with chalkboard paint and attach a hook to the back to hang on a wall. A trash can lid, a mirror, an empty photo frame, a floor tile --- almost anything can be turned into a clock with the addition of an inexpensive clock kit. Glue corkboad to one side of a board and hang on a wall to put up notes and pictures with pushpins. Make a unique piece of wall art by cutting the strings out of old tennis rackets, taking them to a glass shop and having a mirror custom made to fit in the frame.
An old door can be turned into an eye-catching accent piece to be stood in a corner or leaned against a wall. First clean it and sand it down; now you've got a black canvas to be beautified. Paint it. Nail on decorations. Etch or carve designs. If there are decorative panels, paint them one color and the rest of the door a complementary color. Or cut out the panels and stretch vividly colored fabric across the empty space. You could turn the door into a matching set of wall art by having it sawn in half, decorating as you choose then mounting on a wall. Decorate an old screen as a holder for jewelry.
If you find an old wheelbarrow in your garage, turn it into a planter. A wheelbarrow planter is a quirky accent piece that can liven up any yard, porch, or garden. Any size or style will work. Just place the wheelbarrow wherever you want it, drill holes in the bottom for drainage, add potting soil and plant seeds. Grow greenery to add a natural element to an urban patio, flowers to add color to a drab landscape or herbs for cooking savory meals.
Swipe a few bottles and empty jars out of the trash can or glass recycling bin. Turn them into planters. Drill a few drainage holes, fill with dirt and plant seeds. Turn them into knickknacks by filling them with seashells, sand or pretty pebbles; seal closed with a cork stopper, layer of glue or the lid if you still have it. Or use the bottles to give furniture a whole new look: Break them into pieces and glue them onto window frames, trunks and stool legs to make a mosaic.