"Kehne Ki Nahi Baat" (Mohammed Rafi singing Laxmikant-Pyarelal) from Pyar Kiye Jaa, 1966
This song has everything! Big band brass! Surf music and Chuck Berry influences! Social protest lyrics! Groovy head-shaking choreography! Beatlesque harmonies! Animal noises! A marching band! Shashi-shimmy!
This is the most exuberant Shashi dancing I have ever seen, and it is a thing of beauty. He hops and skips barefoot down the sidewalk, leading a ramshackle conga-ish line of backup fellows, he twists again like I wish I did last summer, and he even gets his Elvis on for a moment, thrusting his hips this way and that. He gets his proto-SRK on too, eyebrows working overtime. He does not yet have his 70s masala curls, but his hair is long and loose enough that it dances too, easy breezy in the beachfront sunshine. In short, he is Shammi - yet with all his magical Shashi powers too.
Update to post (May 27, 2008): Thanks to reader Sumanth, I've just learned of the Tamil version of this movie - or rather, the Tamil original (if imdb's date for Kadalikka Neramillai is to be trusted). Watch that movie's version of this song here and be amazed at how much the Hindi version copied! Same location! Some of the same dance moves and props! Whoa.