First, start by creating a list of 4 letter words. These can be any words at all. Here's a few to get you started:
This game is played by assuming each word is an acronym. Players must create definitions for the acronym on the fly by saying the first word out of their mouths. So for example the definition for RING might end up "Robert Ingested Naughty Gophers" with each word in the sentence being contributed by a different player. There is however a pattern to the definition. The first word is typically a noun or a name of someone. The second word is usually a verb. The third word is usually an adjective and the fourth word is typically another noun.
To start the game the host points to a player and says the word - in this example we'll say the word is LEFT. The player then starts by saying the first noun they can think of starting with "L" such Lizards. The person on their left then must say the first verb they can think of starting with E such as 'eat'. The next person says an adjective starting with 'F' such as 'flowery' and finally the next person finishes with 'tarts' which starts with T. So the final sentence is "Lizards eat flowery tarts". The sillier the better!
The key to the game is to get players to say the first words that come to mind and to move the game along quickly. After one sentence is done, move quickly to the next player and throw out another word. This is great for laughs!