The C-Men tee design is for the X-Men fans and The Big Bang Theory fans.

This concept is an obvious given idea directly from an episode of The Big Bang Theory as seen in the clip above. It is not original as this idea has been done elsewhere in The The Big Bang Men Tee tee. The reason it is funny for those people whom lack a sense of humor is that Sheldon is oblivious to "C-Men" sounding like "semen". Sheldon and his "C-men" are confronting Will Wheaton the Archenemy. The main characters are included. Howard has his robotic arm that his body part was stuck in. Leonard is swinging as Beast does, Raj is throwing wads of paper with horrible aim and Penny is just standing there oddly as Jean Grey does except she seems out of place as she has no power or attack. Probably due to a lack of a costume like Jean has. There are also elements from other episodes added to the mix like the like the Einstein Approximation episode shown below.

As for the artwork, it looks like an actual comic book cover but the artwork isn't as detailed or as good as some actual mainstream titles such as X-Men which is being parodied. There is lots of action and decent perspective. It has good solid colors and simple tonal shadows with no gradients. Wheaton's face should be in shadow.

Overall the C-Men is a good reference tee for The Big Bang Theory fans.