Donation of the day.
Today, I'm donating the first two books in the Worst Case Scenario Ultimate Adventure series, Everest and Mars.
While I haven't read them—as much as I love Choose Your Own Adventure-style books, I just never found the time—I can't really image two franchises MORE well-suited to a mash-up than CYOA and The Worst-Case Scenario Handbooks.
Granted, this isn't technically a case of two franchises teaming up, as it's just CYOA-STYLE, and not CYOA-BRAND, but you know what I mean.
Oh, and while I've been remiss in posting about it, my Donate A Book A Day vow has not faltered! On the days I didn't post, I donated Proxy, The Beautiful and the Cursed, and The Secret Ingredient.