My upper-level undergraduate Renaissance Poetry course is the most fun I've had teaching- EVER. And why? Because one of our rare books librarians decided she wanted to collaborate with me on the course. I said "yeah, sure, why not?"- I already bring my students up to rare books several times a semester. It might be nice to bring the rare books to them for starters. So long as she let me lead the discussion. And it's working really well.
Every day she brings a different old book to class, sometimes 2. Her choices always tie in to our discussion and reading.
Last week we read "Astrophil and Stella," and for our second day with the sonnet sequence, for a discussion on Sidney's "school-boy writer" persona, she brought along a 1591 edition of the poems, plus a 1627 book of grammar-school rules. When I suggested we read a few of the sonnets aloud, we passed around the early modern book, and the students got a chance to struggle with reading from a 16th century text. Which generated quite a few giggles, but also brought the experience down to earth. Pretty soon, they were volunteering to read, which is rare at a place like this (maybe rare everywhere? Except for the peppering of theatre majors in most upper-level English classes).
Anyway, teaching's fun this year. Every day, actually. I highly recommend that everyone try this out- if you haven't already. I'd be interested to read in the comments section about some of your own experiences with collaborative teaching. Did it work? Did it backfire? (I'm still a bit worried that the students will remember the old books but not Sidney).