The second season of Maria-sama ga Miteru or Maria-sama ga Miteru Haru is a continuation of the first season.. a story about the members of Yamuyuri Council, the ordeals they go through in making the school a better place and their relationships which each other. While the show is generally episodic, there is a fair amount of drama (with a little of it being melodrama) and character development which are the show's strongest points.
However, the DVD-only specials of the Maria-sama ga Miteru Haru are almost the complete opposite of it as far as the mood and themes go. The specials are very light-hearted and comedic.
If you are expecting the specials to be exactly like the actual series, you might be disappointed.
The art style is probably one of the things that stick out about the specials. While in the actual show each character has relatively realistic-ish proportions, everyone in the specials are basically chibi versions of themselves.
Each special episode is very short (no more than 2 minutes including a very quick opening and short credits) and contain multiple scenarios. All of them parody random scenes taken from the actual second season.
Basically each scenario pretends like the main characters scenes are getting "filmed" and decide to show some outtakes. The dialogue/actions in the scenes start off like how they were in the original show but either someone messes up a line, exaggerates an action or emotion or something really random happens that messes up the "take".
While I admit that some of the parts were kinda funny, I thought a whole bunch of the scenarios and outtakes were a bit too cheesy for me to enjoy more.
It is worth noting that to fully enjoy these series you should watch the whole original Maria-sama ga Miteru Haru series before watching the specials so you can understand the scenes and jokes better.
If you liked the original series and are looking for a fun parody of some scenes of the original series you should definitely check these out, you may like them more than I did.
If you haven't seen the original second season (or even the first) and are interested in an episodic-ish show with pretty good drama, character development, and interaction you should definitely check those out before watching these specials.