I voted for The Enchanted Forest book 1, since I love that series.
It is one of my all-time top-5-or-so favorites, and as I said elsewhere I am positive you will love it.
Rather disappointing that it seems so few have even heard of it...
I also voted for the Hitchhiker's Guide, which has a similar zany humor although the last two were a little too dark and didn't work as well.
Haven't read most of the others, so I didn't feel comfortable recommending them.