In terms of storybooks, I think Jon Klassen's I Want My Hat Back may be fun. The vocabulary is a little challenging, but the illustrations make the story is very clear. My co teacher did a couple lessons on it with 5/6th grade and they enjoyed it a lot, but fair warning- the ending is a little dark and some co teachers may feel it's unsuitable.

If you have several lessons to plan, I think that Anthony Browne's Things I Like would make a good multi-lesson project, especially if you do something like book-making. The present continuous structure is something 5th and 6th grade know, but the vocabulary is a little more advanced than what they'd normally study and they'll get to learn some ways to better express themselves in English. My co and I did that kind of project with our 5/6th grade afterschool class last year.