Put tracking stickers on objects that you lose often, like keys, phone, wallet etc. Tell the app on your device what THAT sticker is on ("car keys"). Then when you need to find it, use the app to find that sticker (and your keys).
15 Fun Doorstops. You've Never Wanted A Doorstop This Much!
Pet Plant: this high tech pot reads soil for nutrients, humidity, and temperature. Then the LCD screen displays a face showing how the plant 'feels'. This would probably be the only way to keep a plant alive under my care.