Original Purpose: Tension control.
Aha! Use: You can consign this heavy-gauge spring (about $2 at hardware stores) to the garage or the tool shed and it will do exactly what it was designed to. But how boring and predictable would that be? Give it a place of honor on your desk or kitchen counter instead and — presto! — you've got yourself a mini horizontal file for bills, mail, and invitations.
Reward: It's beautiful and cheap, and if you spotted it in an art gallery, you probably couldn't afford it.
Other Uses: Postmodern photo display (for all those shots you refuse to hide away in an album). Recipe holder while you're cooking. Three-dimensional to-do list: Write your tasks — monumental, minuscule, miscellaneous — on index cards. When you need to reorder your priorities, send the cards farther back or forward. When you accomplish something, remove the card from the spring.