The middle of May; approximately May 15th. This is the general date at which all high-school seniors have gotten where they want to be and thus, stop caring about high school. This coincides with the point in the grading term in which they can still pass their classes without doing any work from there on out.

This is a play on words, referring to the Ides of March. Much like Caesar's downfall, the Ides of May lead to the downfall of many seniors because they often fail to do the gradebook math correctly (their brains are fried, give 'em a break).

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.

May 15th. This was derived from the Ides of March which is when Julius Ceaser was killed.