Well in essence Happy Pants are part of our unofficial uniform, and occasionally out semi official uniform :). They are made from a Pyjama pants pattern and using all those fabrics you buy and love but never actually wear unless you're under the age of five because they're too bright and out there.
The theory behind Happy Pants is that it is impossible for you not to be happy when you're wearing such happy fabrics.
Anyway I'm off to guides tonight for our AGM and to sew some more Happy Pants :)