If you have an office job, chances are very high that you spend a lot of your time using a keyboard and mouse. Many of us never really think about these critical interface devices, but without them, many jobs wouldn’t be possible, or at least would be very different.
Personally, I started using a trackball a few years ago, and recently started using a relatively inexpensive mechanical keyboard. Though not that unique, they hopefully improve my efficiency somewhat.
If you’re already looking for out of the ordinary peripherals like mechanical keyboards, perhaps you’d like something absolutely unique. If that’s the case, you could make your own computer mouse, as seen in kit form here. The kit provides parts for a mouse, including a top shell and bottom base plate, as well as wiring and screws. You’ll just need to provide an Arduino board to interface between the mouse and a computer.
Alternatively, you could print your own with files for this mouse, which can be found on Thingiverse. You’d need to provide your own electronics, but the optical sensor board used in the kit can be found here, so it should work nicely.