The Wii Remote, WiiMote for short. I have one that's been inside a box for years. Since my computer does not have a bluetooth card, I couldn't do anything with it (my Wii's been gone for even longer). On the usual reading random wiki pages that peek my interest, The DSU protocol popped up. Client-Server structure.
As my Raspi has a bluetooth card, I built linuxmotehook2, paired the wiimote, opened Dolphin, and pointed the client to the server.
It works, it does the job.