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xkcd #2937: Room Code
(imgs.xkcd.com)
Alt text:
Sorry to make you memorize this random string of digits. If it helps, it can also double as a mnemonic for remembering your young relatives' birthdays, if they happened to have been born on February 5th, 2018.
My brain: "Ugh I suck at memorizing random numbers! I just know I won't be able to remember that."
Also my brain: "Oh a fire/medical emergency/... - lets call emergency services!" immediately followed by "♪ 0118999881999119725...3 ♪ "