My daughter just learned this very cute spelling mnemonic at school:
"Big elephants can always understand small elephants "
Not sure how much better that is than just learning the spelling , but the kids seemed to find it fun .
Anyone else learned any interesting mnemonics lately?
Right here, in fact. The genus of yew trees is taxus. Someone (Polycarp?) said that’s why they’re planted around cemetaries, because the two inevitabilities in life are death and taxus. I don’t know if knowing the genus of yews will ever be useful to me, but I know I’ll never forget it.
“Some say marry money but my brother says big boobs matter more.”
It helps you remember whether cranial nerves I-XII are sensory (S), motor (M), or both (B).
Can Orville see down my pants pocket? Tom Jones can. Tom’s queer.
Geologic periods, from cambrian to quaternary, learned early '80’s, which is recent to me.
Compass deviation: True Virgins Make Dull Companions. (True heading plus Variation equals Magnetic heading, plus Deviation equals Compass heading. ‘Plus’ means ±, depending on where you are.)
I think this has changed since I learned it, but the SA report (weather) was: Can Vera Make Tom Dance Without Any Toes? (Ceiling, visibility, millibars, density, wind direction and speed, altimeter, trash (remarks))
When I was a kid a friend helped me remember how to spell “secretary” by telling me it was the kind of job a cockney spy would do: Secret 'Arry. Even now that crosses my mind when I type the word.
Me too! I rearranged it in my brain a bit, so now it is “Yew can’t escape death and taxus.”
There are so many medical mnemonics. You know that far away look doctors get sometimes when you’re sure they’re not paying attention? They’re usually running through mnemonics in their head. 
We had some in nursing school, but not as many as they get in med school.
I’m partial to:
RN CHAMPS for the various types of Shock:
Respiratory
Neurogenic
Cardiogenic
Hemorrhagic
Anaphylactic
Metabolic
Psychogenic
Septic
and LARA CROFT, for the possible causes of abdominal pain during pregnancy:
Labour
Abruption of placenta
Rupture (eg. ectopic/ uterus)
Abortion
Cholestasis
Rectus sheath haematoma
Ovarian tumour
Fibroids
Torsion of uterus
Have No Fear Of Ice Cold Beer - Hydrogen, Nitrogen, Fluorine, Oxygen, Iodine, Bromine - The diatomic molecules.
I love that one.
Never Ever Serve a Woman - North East South West
All King Edward’s Horses Can Make Bigger Fences
The letters around a dressage arena, counterclockwise.
People need a mnemonic to remember the cardinal points? 
Or, if you want to remember the names of the nerves, “Oh, Oh, Oh, To Touch And Feel Virgin Girls’ Vaginas and Hymens.”
“Nerve 0” in other animals is sensory, too.
For remembering the color bands on resistors in order:
“Bad boys rape our young girls but Violet gives willingly.” Other versions sub in “black” etc. at the beginning, which is much more offensive but does give more information on whether it’s supposed to be “black” or “blue.”
6 year olds who still don’t remember which is their right hand?
You forgot the “Cold” - Chlorine.
I learned this as “Never Eat Sour Wheat” but never saw the point of it. When I was a kid, I’d just think of “NEWS,” and I’d remember the correct zig-zag to get it right.
We had a couple of spelling mnemonics when I was a kid…
“A rat in the house may eat the ice cream” for arithmetic.
“George Earl’s oldest girl rode a pig home yesterday” for geography.
Nobody used ROY G BIV for the colors of the rainbow?
Red, orange, yellow, green, blue, indigo, violet
I thought that was one of the classics, along with “King Philip Came Over From Great Spain” (for taxonomy in bio) and “Please Excuse My Dear Aunt Sally” (order of operations).
Kentuckians park cars on freeways going south.
(Kingdom, phylum, class, order, family, genus, species)
We always said “King Paul, Charles of France, got stoned.”
I learned this many years ago to remember the street layout in downtown Seattle. It was a great help when walking before we had smartphones.
From South to North.
Jesus Christ Made Seattle Under Protest
Jefferson, James, Cherry, Columbia, Marion, Madison, Spring, Seneca, University, Union, Pike, Pine
“Kings play cards on fat* green stools” here,
“My Very Eccentric** Mother Just Sent Us Nine Pies.” Planets of our Solar System. A bit obsolete now due to Pluto’s downgrading, and it does change when the orbits of Pluto and Neptune shift.
*Flat is probably the one we were taught, but my memory says that “fat” is the most accessible.
**Or excited