I’m gonna admit it up front: I am not a dog person. Which, in a class of second graders, usually makes me the only one. Second graders just eat up dog books.
Speaking of eating, you can read this one to kids in second grade, or they can read the dog-arrific poems to each other, and they’ll beg for it the next three years:

It’s great for April’s poetry month or a rainy day or the day before vacation or anytime in between.
Second graders also adore the amazing sense of voice in this book:

I’ve used Help Me, Mr. Mutt as a mentor text before, because its format is consistent and replicable by students:
Letter from dog bothered by its owners behavior (and the household cat), including some kind of chart, table, or graph;
Response from Mr. Mutt giving the dog ideas about how to assert him/herself as the alpha in the household;
Haughty response from The Queen, the cat who lives under Mr. Mutt’s desk.
After we read and enjoy the book (and second graders REALLY enjoy it, especially if you bring out your wacky voices), the kids go to the computer. As Moodle is required beginning in third grade, this is an introductory Moodle activity for them. In pairs, they log in and orient to a discussion forum a new letter from a bothered dog to Mr. Mutt. First, they respond in the voice of Mr. Mutt (inevitably adding, “Remember — You Are Top Dog!” at the end). Then, they choose a colleague’s Mr. Mutt letter and respond to that in the voice of The Queen. Since The Queen writes her letters on pink stationery with a fancy flourished font and her paw print, students often ask to make stationery (we use KidPix or PowerPoint, and, with adult help, save as an image and upload it into the Moodle discussion forum. Tip: You have to type one blank space or another character before Moodle will let you insert an image). It usually takes two days from start to finish in a fixed schedule, but if you have students who struggle, you might plan to have extra finish-up time on the third day. Those who finish early can go back and point out the best, funniest parts of their colleagues’ work.
This lesson of mine appeared in the October 2009 issue of School Library Monthly as “Moodle and Mentor Texts: Help Me, Mr. Mutt!” and it’s still one of my favorites because I think that it provided a developmentally-appropriate, high-interest way to use Moodle. The discussion forum gave each student access to everyone else’s work, which facilitated the responses needed.
If you teach older kids, you could replicate this with a new book, Sorry I Pooped In Your Shoe, published by Andrews McMeel and scheduled for release today:

The book features over 20 letters of varying tone and voice from the dog (who always has a name) and the owner (known as Alpha, or, in one case, Beta). Now, i have to be honest — a book with poop in its title isn’t for all schools, and you’ll also find crap and a– in it.
But here’s a sample (a screenshot taken from the NetGalley pre-publication copy):

Great voice, some persuasion, and even, in some cases, that most-vaunted Common Core goal: constructing and defending an argument.
You could select a few of these to share with the class (I’d say grades 3-8), then ask them to identify an annoying behavior that a pet they know does (or an annoying behavior that owners do “to” their pets). Finally, ask them to craft the letter in the pet’s voice, explaining why the pet’s behavior is ideal, why the human’s behavior is un-called for, or why the pet is, quite frankly, superior to the human.
Or, to make a research connection, try putting a spin on a less-than-interesting word-moving (McKenzie 1996) report and ask students to imagine that their parents have just adopted their animal as a pet. What behavior that they learned from doing research might that animal manifest in their home that might cause a problem? Conversely, imagine that the human were writing to the animal!