Sam and Max: Beyond the Alley of the Dolls
The introduction to Beyond the Alley of the Dolls is great, featuring an homage to zombie movies everywhere as Sam deals with the slight conundrum of his friends taking a strange amount of delight in dispatching cloned, half naked versions of himself. The rest of the episode doesn't quite live up to this beginning, mostly because the puzzles were the least interesting and unique of the season. You were mostly using psychic toys you'd already played with before, and there wasn't much new to the gameplay, not even on the gimmicky side. It was still well made, it's just all of the fun came from the story rather than the game itself.
Luckily that story is pretty great, with ghost summoning, gigantic underground cloning facilities, Lovecraftian horrors, forbidden interspecies love, and epic climaxes at famous historical landmarks. A surprising amount of the important parts for the entire season-long arc are explained, although of course things get turned on their heads at the end in the last cliffhanger before the final episode. It all remains manageable despite the scope, thanks to solid writing and good voice acting, and it's also probably the series' most visually ambitious episode yet. If only those puzzles were a bit better! Oh well. It's still yet another good entry in the series, and a nice warm-up for the finale.