Sora no Manimani is a basic highschool comedy. There's nothing really special about it at all. A guy, Saku, moves back into his hometown after about 10 years amd gets dragged into his highschool's Astronomy Club by an energetic and annoying childhood friend. The club is in poor shape with minimum members and almost zero funding. This, of course, doesn't stop their midly entertaining club activities (which usually just involve stargazing). By the end, not much is acomplished plot-wise and there is barely any character development.
The characters are genertic (bookworm, energetic girl, sickly guy, love rival, etc.). Not too much is interesting about them. Although I did like the small bits involving Saku and the student council president.
The show did have a few enjoyable moments for me, and the overally show improved as the show went on. I love astronomy; I took it in my first year of university, so I could connect things from this anime to things I learned in that class. I probably enjoyed this show more because I've been stargazing and studied constellations (which I really enjoyed). However, my love of astronomy didn't help this show very much, although it made it interesting. If I wasn't into astronomy, this show would no doubt get a lower score ;P