What is the smallest metal object you can ground yourself with?
If you are installing a CPU in a motherboard, you don't really care about grounding - what you really want to do is to make sure that you, the CPU, and the motherboard (and any tools) are all at the same potential.  If you have one of those grounding bracelets, you should connect its ground lead to the computer case or motherboard Ground - whether that is "Really Ground" or not is not particularly relevant.