I had a lot of fun with Redshirts, it doesn't take itself too seriously it's just a good time. I find that a lot of Scalzi's stuff is like that. I think my favorites have been The Kaiju Preservation Society (audio version also narrated by Wil Wheaton), and the Lock-In books (in which the main character is never explicitly gendered, so there are two audio versions of each book: one narrated by Wil Wheaton, and one by Amber Benson).