Sousuke Sagara is far from the average high school student - not only is he highly trained in military tactics, he puts his knowledge to use in every single applicable situation (and even those nonapplicable ones.) So, when confronted with high school, he tends to turn average high school experiences into off-the-wall adventures. Love letters become terrorist threats and field trips become commando operations; his survival depends on the watchful eye of his best friend and classmate, Kaname. Together, they may just make it out of high school alive...
These two titles take the serious shows that they are attached to, flip them on their ear and create hillarious parody shows of the sorce material.
Both are even more funny if you had at least seen a few episodes of the respective series first, but you do not necessarily have to.
So if you enjoyed the short mini storied episodes of one, you might enjoy the other.