A day spent ingesting ecstasy tablets, presumably if someone has nothing to do for that day or the next. A good way to spend a sunny day, the most successful pill days are to be had by university students in the summer term when they have no exams, no coursework, and a sunny day in a sociable and picturesque setting at their disposal. Alternatively, a good pill day can be had at music festivals when there is little or no constraint as to what you can or can't do.

Smoking green, having a few beers or ingesting other drugs can occur, but the main impetus of the day is to be knocking the little 'uns back.

The safeguarding of Earth and other worlds from biological cross-contamination (i.e. billionaires with too much time on their hands).

Also known as “planetary protection.” Planetary protection / quarantine “reflects both the unknown nature of the space environment and the desire of the scientific community to preserve the pristine nature of celestial bodies until they can be studied in detail.”

There are two types of interplanetary contamination. Forward contamination is the transfer of viable organisms from Earth to another celestial body. Back contamination is the transfer of extraterrestrial organisms, if such exist, back to the Earth's biosphere.