Sine Opposite/Hypotenuse, Cosine Adjacent/Hypotenuse, Tangent Opposite/Adjacent. Most of us just learned SOHCAHTOA. 
Stalactites: ceiling
Stalagmites: ground
Sohcahtoa. The great, fictional, mathematically inclined Iroquois chief.
Jesus Christ Made Seattle Under Protest
Order of downtown Seattle street names (South to North)
My daughter was pretty young when they learned this. It was probably more to help them remember what order they went in. And it’s more fun for a kid.
More spelling: Two "A"s separate two "E"s…
Now amended to: “My Very Elegant Mother Just Served Us Nothing”?
Poor Pluto… I liked Pluto… 
Stalactites cling to the ceiling.
Stalagmites grow from the ground.
When I was taught resistor markings, the officially approved mnemonic was “Big Buicks Run On Yellow Gas But Volkswagens Go Without”. Although the lab instructors always added the “Bad Boys Raped Our Young Girls But Violet Gave Willingly”, with a warning not to use it in mixed company.
Substitute “Black bastards” for “Bad boys” and the mnemonic is strengthened by distinguishing between the black and brown bands, while bumping the offensiveness up by a *large *factor. :eek:
One of my dad’s training manuals from the war gave this mnemonic for causes of machine-gun stoppages: “Freddie fêtes Elsie 'cos she expects enjoyment”. If the version the instructor quoted orally was “fêtes”, I’ll eat my fêteing hat. 
Late College Parties Never Produce Sexy European Girls That Drink Heavily Even Though You Look
For the Lanthanide elements
We learned GRACE in History for the conditions of the Treaty of Versailles.
Guilt, Reparations, Alsace-Lorraine, Colonies… and the last once which I have long since forgotten 
TV Makes Dull Children
or
True Virgins Make Dull Companions
Used for navigation
For astronomy: “Follow the arc to Arcturus, then speed on to Spica.” If you extend the curve of the arc of the Big Dipper’s “handle,” you can find Arcturus (Alpha Boötis) and Spica (Alpha Virginis). (You can also find Polaris by taking the two stars at the end of the “bowl” - Dubhe and Merak (Alpha and Beta Ursae Majoris) - and extending the distance between them five times.)
Two streets per letter.
My favorite memnonic is “I before E except after C, or when sounded like A as in “neighbor” and “sleigh” or in certain other weird words.”
I guess we never needed to know the kingdom - for us it was “Please Come Over For Gay Sex”.
Hi Everyone. Let’s Pitch In ‘N’ Get Cracking Here In Louisiana Doing Right, Eh? Now Then, Hateful Rich Overbearing Ugly Guys Hurt Royally Everytime Someone Eats A Radish Carrot Hor’derve And Never Does Dishes. Eventually Victor Eats Lunch Over Peoria Mit Ein Noyesburger Tod.
Please give generously. Thank you.
I learned:
Easter Bunny Gets Drunk After Easter.
The solar system one I learned was:
Soon, Many Very Early Men Ate Juicy Steaks Using No Plates.
Sir, I send a rhyme excelling,
In sacred truth and rigid spelling,
Numerical sprites elucidate,
For me the lexicon’s full weight,
If nature gain, not you complain
Tho’ Dr Johnson fulminate.
My Very Easy Method Just Sums Up naming Planets.