the dark side of Sunday

[frindle]

Hello. I'm not sure. In the context below, does the dark side of Sunday mean blue Sunday?
Please help. Thank you.


--------------------
(G hates school. So he lives for Friday. His teacher is saying to G on Friday afternoon.)
"Happy weekend, G. See you on the dark side of Sunday. Get it?
The dark side of Sunday? Monday!"

[JMurray]

In the context below, does the dark side of Sunday mean blue Sunday?
"Happy weekend, G. See you on the dark side of Sunday. Get it? The dark side of Sunday? Monday!"

The teacher explains the meaning, the dark side of Sunday is Monday. I've never heard the expression but it's like the far side of the moon being the dark side – the "far side" of Sunday is Monday.

not a teacher