A company with a funny name has made some of the most interesting computer input devices of recent years. Ploopy got its start with trackballs, at a time when bigger companies were exiting the space. Since then, the company has made trackpads, pointing sticks, and dials. Now the company is bringing some of those gadgets together with the new Ploopy A+. It's a trackball mouse with eight buttons... two of which also function as dials. Like all of Ploopy's hardware, the new trackball is an open source device - the company posts hardware designs, firmware, and other materials on…