Via H_I_R’s bookmarks I found the following post: Make use of your old PS/2 ports. The blog is currently down. Coincidence? 😛

The idea of the post was to take your unused PS/2 ports and use them as a power source to charge your mobile phone, which would otherwise support charging through USB. The idea is cool, however there is a possibility for you to fry your motherboard (or part thereof).

From the source of all wisdom Wikipedia: USB can supply 500mA or 100mA of power, however PS/2 can supply only 100mA. If your try to power a device which needs more power, there is the possibility that you will fry your motherboard! Also, 100mA is the upper limit for PS/2 and I really don’t like pushing equipment to its limits, but maybe that’s just me.