Attaching a connection to anything that is attached(buried in,etc) to the outside ground (or earth if you prefer) will effectively 'ground' it.
Therefore most water pipes/taps etc (as long as the main pipe into the premises is metal and also the house pipes as well, nowadays there is a trend toward plastics) will be at 'ground' (also called earth - sometimes abbreviated to Eth on wiring diagrams) potential.
The same is with the earth (ground) connection of a power outlet. (You will find that these are usually wired to either a water pipe or a stake driven the appropriate distance down into the ground outside the premises. Don't know the rules where you are but if you go to the front garden tap (especially if it is on the wall of the house ) it is not unusual to see Eth wires attached to the water pipe feeding the tap or a stake close by - the theory being that the tap being used , with spilliage, keeps the ground under/around it more moist than other places therefore ensuring a low resistance Eth point.
A table will not be an effective earth because it may be made of timber (not a good conductor of electricity -more like an insulator). If it is a metal table (legs especially with no plastic/rubber feet) then it depends on what it is standing on and even then it will probably not be any good, if what it is standing on is also acting as an insulator
Equipment that has a metal frame with a 3 pin power connection will provide a good point to connect to earth, (plugged in of course - the power outlet doesn't have to be switched on for the earth to be connected). Be careful with this if you still have the power on and the covers off, it could be deadly. Do not know what they are called where you are but it pays to have your power outlets connected to an RCD in the home's power box (residual current device or safety switch). http://www.explainthatstuff.com/howrcdsw...
If there is not one permanently installed in your home's power box. maybe you can get something portable, similar to this, where you are. http://www.clipsal.com/Trade/Products/Pr... )
If however the equipment has only a 2 pin power connection and/or it states that it is 'double insulated' then there will be no earth connection to the equipment.
Hopefully some of this information is a good starting point.