The road so far:
Day 01 - Best book you read last year
Bulgakov, The Master and MargaritaDay 02 - A book that you've read more than 3 times
Stemmle, The Man Who Was Sherlock HolmesDay 03 - Your favorite series
Pratchett, The Discworld seriesDay 04 - Favorite book of your favorite series
Day 05 - A book that makes you happy
Day 06 - A book that makes you sad
Day 07 - Most underrated book
Day 08 - Most overrated book
Day 09 - A book you thought you wouldn't like but ended up loving
Day 10 - Favorite classic book
Day 11 - A book you hated
Day 12 - A book you used to love but don't anymore
Day 13 - Your favorite writer
Day 14 - Favorite book of your favorite writer
Day 15 - Favorite male character
Day 16 - Favorite female character
Day 17 - Favorite quote from your favorite book
Day 18 - A book that disappointed you
Day 19 - Favorite book turned into a movie
Day 20 - Favorite romance book
Day 21 - Favorite book from your childhood
Day 22 - Favorite book you own
Day 23 - A book you wanted to read for a long time but still haven't
Day 24 - A book that you wish more people would've read
Day 25 - A character who you can relate to the most
Day 26 - A book that changed your opinion about something
Day 27 - The most surprising plot twist or ending
Day 28 - Favorite title
Day 29 - A book everyone hated but you liked
Day 30 - Your favorite book of all time
Day 04 - Favorite book of your favorite series
This is probably a rather obscure choice, but I can't help it, I love Monstrous Regiment to bits. Also I'm totally shipping Polly/Maladict, because seriously, it's almost canon, y/y? And I don't even do shipping usually, plus I'm so bored by the broody but elegant vampire trope (I'm usually more for the Count Orloks of vampire lore). But it's Pratchett, lame tropes get awesome just by association in his books and wow, does it get awesome. So Maladict can brood as much as he wants as far as I'm concerned, and dazzle his way up the army ranks, and make sweet love to Polly along the way. Don't judge me. That book speaks to my inner squee.
I'm coming up empty with any other reasons why this book is so great that aren't major spoilers, but let's just say, when I first finished the book I was like, OKAY, disbelief so not suspended, dude. That shark you jumped there had whale-size proportions. Then I thought about it, and I realized that I actually loved that he went all-out in the most batshit crazy way possible; anything else than sea animal sports would have been a let-down. After all, we're speaking of a fantasy world that is supported by four elephants standing on the back of a turtle. Also we have a ragtag bunch of misfits (a vampire, an Igor, a troll, two runaways, a nutjob) with SECRETS trying to survive the day, what's not to love?