If you were a 9 year old kid in 1974, chances are this show was your introduction to science fiction. The show featured a stellar lineup of sci-fi authors who wrote many of the show's best episodes.
David Gerrold, DC Fontana, Ben Bova, Theodore Sturgeon, Larry Niven, hell, even Walter Koenig all contributed thoughtful and fun episodes during the first two seasons of The Land of the Lost.
It was heady stuff for me. I didn't know you could control reality with a bunch of crystals aligned in a matrix stored in a big shiny pylon. I was stunned to find out that the Sleestak were really Enik's descendants and not his ancestors. The concept of devolution had never occured to me before that. The idea of time as a closed loop was also fascinating, and I always wanted to know more about the alternate reality the Marshalls briefly encountered ... you know, the one where Holly wore a solid yellow shirt instead of the red and white checked one.
The show also introduced me to the idea of disillusionment. Unfortunately, the show jumped the shark starting with its third (and final) season. The sci-fi plots vanished in favor of outrageous kiddie action. The Sleestak (and Cha-ka) suddenly spoke perfect English. Cavemen and Medusas appeared. Enik became a Mr. Spock rip-off. It all insulted my intelligence. I hear that a remake of the show began in the 90s, but only a Paku would acknowledge that fact.
Of course, the best thing about the show was its theme song, presented here in its entireity, courtesy of the Land of the Lost website, http://www.execpc.com/~nolsen/lotl/lotl.html which now appears to be out of service. Sigh.
Marshall, Will and Holly
On a routine expedition
Met the greeeeeatest earthquake ever known
High on the rapids
It struck their tiny raft (aaaaaaahhh!)
And plunged them down a thousand feet below
To the Laaaaand of the Lost ...