My favourite part (anime-wise, at least) was the season after Fumoffu, but definitely agree on Fumoffu being gold. I got my housemate to watch it last year and we had to stop several times because he was laughing so hard, genuinely great stuff. I think the episode with the rugby team was probably my favourite.
Argh, I feel like I should know this one. May I ask if it's a fantasy setting?