Hi,
I saw a book today called "Creative Designing With Polymer Clay" or something like that.
[...]
So has anybody ever used it? anyone got any more info? and would it be any use in creating custom parts for robotics(considering that its a plastic that can be moulded easily into any shape and then permanently hardened)?
Yes, it's sold under (among other) the names Cernit and Fimo Clay in hobby stores (the kind that sells "pearls" and DIY "jewellery" and such), it comes in all sorts of colors (I have a pack of glow-in-the-dark right in front of me) and "finishes", like granite stone, silver metal, neon colors, etc. etc.
It's used extensively for making "jewellery" (for lack of a better term), but anything goes. When my sons were kids, they loved making refrigerator magnets (so much that I cannot see my fridge for magnets

).
It is not for super precision, as it flows a tiny bit when being baked and afterwards, it's like a semi rigid (or is that semi soft) plastic it can be filed and cut with care and sharp tools, I wouldn't try to make a screw thread in it, bot a bolt through should be OK - just make sure there's no cracks in it before it goes into the oven - that means hand wash immediately before working with it and perhaps latex gloves, as skin oils and grime will make it not stick to itself.
http://www.sculpey.com/products/clays/sculpey-bake-shopAnd here's what to give dad when he have a Ferrari on his wish list:
Fimo Clay Penndants(He'll probably mention something about you being adopted and all, but he'll love it... Trust me... Or not

)