The USB Karaoke Mute-Mic for the Wii claims to absorb some of your horrible – or loud – singing so you can still have a good time without making the people around want to kill you. I don’t know if the mic works, but if it does, will karaoke still be fun if you can barely hear your own voice?
You can order the USB Karaoke Mute-Mic at Japan Trend Shop for $80 (USD). Also works with Windows XP and Vista. No karaoke game or music included.