.

A guy sent a list of ten puns to his friends and asked them to tell him which of the ten puns made them laugh. No pun in ten did.
Nerdy puns:
Wanna hear a sodium joke?
Na.
How about a potassium joke?
K.
I made up a uranium joke just for U!
another:
CreamyGoodness said:When I was reenacting I noticed that 99% of the Union side had belt buckles with a simple US stamped on it. I couldnt figure out a way to do it cheaply, but I wanted to make a buckle that said "THEM" on it, and see if anyone would notice.
LabRatBrewer said:another:
I surrender. I can't figure it out.
Hint: QPwC