4. Book Club
Episode: A Tale of Two Cities (3×01)
Season two kind of ended on a whimper. A lot of big things happened. The hatch blew up. The gang went searching for The Others camp. Michael and his son got away. We saw the four-toed statue. It was fine, but I was getting really tired of the show constantly adding more mysteries while treading water with everything else.
3. Desmond Calls Penny
Episode: The Constant (4×05)
Probably my second favorite episode. While the show dealt with time travel quite a bit, this hour of television dove right in and told a complete and fascinating story around it. The Constant has it all: action, suspense, mind-blowing sci-fi, and a huge emotional payoff.