Pet Rock USB
If you're old enough to remember the 1970s pet rock fad, then congratulations on being really, really old. But don't fret! Instead, why not update this fad and prove your youthful vigor to the entire office with a modern take on the pet rock that plugs into your computer's USB port?
The classic pet rock just sat there on your desk, a testament to marketing and human gullibility. The modern version does exactly the same thing for $10, while also tying up one of your USB ports. When co-workers ask about your new pet, just make something up. Ask if they can feel the USB-generated heat or hear its barely audible laughter when you shake it. Tell them it's made out of nanomaterials. Have fun with it.
Want something practical and chock-full of sci-fi awesomeness instead? Well then the next two entries should knock your work socks off.