The final few episodes of season 2 of Farscape, right through to the end of season 3. If you can ignore one or two of the more mediocre season 3 episodes, this is remarkably strong.

You go from the Shadow Depository heist and the diagnosan planet, to getting stuck inside a wormhole, the amazing Different Destinations, seeing Crichton get twinned, the stuff between Moya and Talyn, some decent (and not so decent) filler, until what's left of both crews reunite for the attempt to sabotage Scorpius' project and the heart-wrenching Dog With Two Bones.