User blog comment:Takashichea/Weekly Sket Dance: Ep. 77 - The Campus SKET (Then)/@comment-203.59.66.190-20121208033102/@comment-4800771-20121208064656

We don't know yet. My teammates and I are looking for news articles for confirmation. There's an OVA coming out and a DVD with special scenes that were not aired in Japan. See the link in the comments below.

As for manga, I'm in the same situation as you. Since the series is episodic to an extent, you can skip a lot of stuff without missing much. The last few episodes skipped a few chapters. They finished volumes 1- 15, I believe. I say start reading from volume 16 on the School Trip Rhasody and keep reading. You want to see the differences between that arc. Plus, there are some altercations in Kiri and Himiko's interactions that the anime did not cover.