Cheddar Gorge is a word game often played on the BBC radio comedy show I'm Sorry I Haven't A Clue. In terms of audience popularity is third only to the famous Mornington Crescent and the allegedly obscure One Song To The Tune Of Another.

In spite of the strange name, the rules are quite simple. The gameplay consists of the progressive construction of a sentence, with players adding one word at a time in rotation. Each word must leave the possibility of the sentence being completed in a grammatically correct and meaningful manner, but players are to avoid actually completing the sentence. When a grammatically correct sentence has been formed, the player who added the final word is eliminated. Play continues with the remaining players starting a new sentence. The last player left is the winner.

Although the game could theoretically be played seriously, on ISIHAC it is not. The sentence ending rule is largely ignored, and the end of the sentence is declared almost entirely arbitrarily by Humph sounding his horn. The tortured nature of the fictitious logic by which Humph declares sentence ends is a source of humour; the logic really used is more concerned with comic potential. The sentences constructed are always long and unwieldy, and the panellists play for laughs on several levels. The sentences are often nonsensical, including as many silly turns of phrase as possible.

For example, one sentence included the fragment "...cavorting wildly over a cliff, who was in wuthering mood...", which confounded expectations twice in less than two passes round the four panelists. Firstly "cliff", which initially appeared to refer to a wall of rock, was retconned by the next panellist to refer to veteran rocker Cliff Richard. Secondly, "wuthering" did not receive its expected continuation "heights": Cliff Richard was appearing in a stage production of Wuthering Heights at the time.