Misc

These are the things which don't seem to fit in anywhere in particular:

Useful (Approximate) Data for Physical Calculations. (Some fundamental constants, material data, mnemonics, units & miscellaneous other bits for quick order-of-magnitude calculations.)
Why a "minus one" in sometimes used in the calculation of standard deviations. (Some maths explained qualitatively rather than hidden under opaque algebra.)
How to Stop Ant Infestations Humanely. (Stopping ants entering houses by feeding rather than poisoning them.)
How to Punt. (Some recreational/sporting instruction.)
Silent CD. (Audio files for creating a totally silent CD.)
Patterned Dates. (Calendar dates which have numerical patterns in them.)