In Episode 5, when the contestants have to pick an object in a snake filled room they think is the murder weapon, Lindsey actually puts one of the snakes on the stool.
In the 7th episode, The Rube Goldberg like murders up to that point seemed to shatter Ronnie's mind, resulting in the best murder theory of the season:
Ronnie: Your monkey, who you had trained... You took your murder weapon and handed it to your monkey and he climbed right back up that rope. But right before he went up to the roof, he pulled the pin to the chandelier.
The "What an Idiot" looks on his fellow contestants when he admits this to them at the dinner is also priceless. Needless to say, he was eliminated at the end of the episode.
It becomes even more Hilarious in Hindsight when it's revealed that a monkey actually played a minor role in Ronnie's death; he was being spied on with a hidden camera drilled into the "See No Evil" monkey statue.
It's also become a slightly meta-CMOF in that the monkey has achieved minor Memetic Mutation status in the fandom.
From the same episode, Geno's dancing during the Luau. Especially the dramatic freeze frame of him with that goofy grin on his face.