Equal Rites
The third Discworld novel starts a completely new storyline with no crossover with the first two books. I actually liked this better than the other books because it hit on the sort of underdog themes that I always tend to find appealing: a young girl is trying to become the first female admitted into the school of wizardry. As with the other books in the series, this one is filled with vivid, interesting characters and silly anachronisms aplenty.