The WiiControl is one modder's solution to avoid overheating when WiiConnect24 isn't running a fan. An external LCD displays the internal temperature at all times. If the heat rises past 35°C, the Wii's fan kicks on just like it should have in the first place.
http://www.xtremtuner.de/modding/wii...olfront_tn.jpg http://www.xtremtuner.de/modding/wii...rolback_tn.jpg
Here is a video of it in action as well:
Source: Xtremtuner.de (in German)