Monthly Girls' Nozaki-kun is a twelve-episode humorous caricature of the shōjo manga (and anime) genre. The series follows Chiyo Sakura, a high school girl with a crush on her classmate Umetarō Nozaki. Turns out that Nozaki is the creator of a romance manga called Let's Fall in Love, and Sakura is soon helping him to create it. Several other students are also involved, either directly helping Nozaki, or as unknowing inspiration for his characters.
That's a pretty bland description for what is a pretty funny series. The writers constantly set up standard young-romance scenarios...walking home together in the rain, acting in the school play with your crush, going to the movies, and so on...and then turn them around in crazy ways. They push the genre's standard tropes to the point of absurdity. I wasn't very often surprised by the "twists" since they were pretty obvious, but that didn't stop it from being funny.
I'm glad I read some of the comments about Monthly Girls' Nozaki-kun when I was browsing around Crunchyroll, or else I'd have totally missed it. Normally when a show's description talks about a high school girl failing to convey her feelings properly to a boy, that's a signal to forget about it and move on to the next possibility. The review comments, though, described it as more of a satire or caricature, and that sounded much more interesting.
If you've never read/watched any shōjo manga/anime, then some of the gags in Monthly Girls' Nozaki-kun may escape you. For those familiar with the genre, though, the series is pretty entertaining. I think that would be true whether you love the shōjo genre or hate it - they certainly poke fun, but not in a mean-spirited way.