Things I would like

If, for any reason, you would like to give me a present, then you may find useful the following list of things which I have noticed that I would like. (Obviously there are plenty of other things I would like!)

Alternatively, you may want to consider donating money to a charity - one that I consider worthwhile, and with which I feel sympathetic through my interest in engineering, is Practical Action (formerly ITDG).

Books

I would be very happy to receive second-hand or new copies of any of these. See also my Amazon wish list.

An illustrated book on plant structure, describing the different families of flowers and their anatomy ktl. (I was once shown a rather good one published by Dorling Kindersley, I think, but I have been unable to find it again)
Metamagical Themas, by Douglas R Hofstadter

Things I collect

(though you may wish to check that I haven't already got whatever you are thinking of in my collection first)

Minerals and fossils
Old scientific/mathematical instruments - especially slide rules and mechanical calculators
Old computers

Other items

A "Chinese puzzle ball" - concentric freely-moving spheres carved from a solid piece of material, originally ivory but I would prefer a wooden or jade one
A quartz "crystal ball" or set of Platonic solids
A "radiometer"
A Chinese singing bowl (the sort that sings if you rub two handles on the sides; also, if you put water in one the singing sets up a standing wave pattern that shoots jets of droplets into the air), or one made of quartz
T-shirts (or other pieces of clothing) depicting a fractal (or other interesting mathematical/scientific symbol - but not a slogan)
A lead "cannonball" (not necessarily authentic)
...or pretty much anything scientific, technological, mathematical, toylike or otherwise interesting!