This year, inspired by attending Ash Wednesday Mass and observing Lent with my friend, I researched Catholic and Orthodox Christianity celebrations. 

Links

Mardi Gras

https://www.catholic.org/lent/mardigras.php

Lent

https://www.catholiceducation.org/en/culture/catholic-contributions/history-of-lent.html

Old Testament and Easter

https://rsc.byu.edu/ascending-mountain-lord/old-testament-easter

Holy Envy

https://uscatholic.org/articles/201908/learning-about-other-faiths-make-room-for-holy-envy-says-this-episcopal-priest/

Uchtdorf – Daily Restoration

https://www.churchofjesuschrist.org/study/general-conference/2021/10/41uchtdorf?id=p28-p37&lang=eng#p28