Hypercube day is the day after Boxing Day, coined by Brady Haran (and to a lesser extent CGP Grey) in the awesome podcast called Hello Internet.

It is the 27th of December.

Called this because of the imagery of a box (as in Boxing Day), inside another box.
boy: I'm going to go for a walk in the woods on Hypercube Day bye!
girl: Wait you forgot your hotstopper
by sirnomnom6 December 28, 2018
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