Here's another dimension to the Pencil dimension study:
Step 1: Measure the diameter of the pencil. Since the pencil is usually hexagonal convert the cross-sectional area into hat of a circle, to get the equivalent diameter.
Step 2: Take a measure tape and measure the average width of your pencil holding fingers.
Step 3: Measure the diameter of the hole your hand makes while holding the pencil.
Now, calculate the stresses generated in your hand due to this peculiar position. Refer some Strength of Material book.
Next calculate the amount of energy expended in maintaining this position. Use some thermodynamics if you like.
Now do some trial and error. Try out different ways of holding the pencil and again calculate the energy consumed. Write some stupid differential equation and find the minima. Voila use that style.
Now try this entire experiment for different pencils and find out a global minima (the previous one was a local minima.)
If you want to make it more advanced you can also do some entropy, enthalpy calculations and do some researc on the type of food which will provide the optimum amount of enregy.
Next, tackle the clothes thingy by noting the ambient temperature on that day and your body temperature. Do some basic Heat transfer calculations (conduction, convection and radiaion.) Pre-determine your comfort temperature and accordingly the thickness of the cloth material and its colour.
Also, if you prefer the same temperature throughout the test then be prepared to shed some clothes along the length of the test, to ensure constant temperature.
WARNING: The non-male gender

is requested not to follow this last tip, for the sake of others.
Thats it. If you are a chemical engineer or a good student of physics and chemistry you understood most of it, if not then forget it !!
Long post eh!!!.. yeah, had some time to while away