Graduation

Fact- The graduation tradition of throwing your caps in the air was started by the graduates of the US Naval Academy in 1912. The graduates, who upon graduation would receive officers' caps, and threw their no-longer-needed midshipman's caps to celebrate their promotions.

Further Info- The practice soon caught on and was copied at graduation ceremonies at other schools. But it's apparently dangerous to throw your mortarboard in the air. There have been several documented incidents of students becoming injured as a result and many schools have banned the practice.

Behind the Scenes- nothing interesting

"Junk"

Fact- The word "junk" was originally a nautical term used for old, useless pieces of rope of uncertain origin

Further Info- the term was later expanded to include other objects that were old and useless

Behind the Scenes- a character on one of my favorite shows, NCIS, Ducky, is also interested in useless, random pieces of information. The latest episode had the team investigating a murder where the corpse was found in a junk yard...of course Ducky had to impart his knowledge to the rest of the team.