Zara and I are both Tina Fey fans and we each read this one in a day. It's a quick read, enjoyable, and I actually learned something, too. It's not only laugh-out-loud funny - it's laugh until you're crying funny. That may have made people look at me strangely on the subway, but I'm okay with that.
In addition to being really, really funny, it gives a behind-the-scenes look at a whole lot of interesting venues: TV production, improv theatre, working on one of the sites hit by the anthrax terrorism of 2001. A fun read - recommended.