Glad you asked. It’s an interesting concept. According to Wikipedia:
Oulipo (short for French: Ouvroir de littérature potentielle; roughly translated: "workshop of potential literature") is a loose gathering of mainly French-speaking writers and mathematicians which seeks to create works using constrained writing techniques. It was founded in 1960 by Raymond Queneau and François Le Lionnais. Other notable members have included novelists Georges Perec and Italo Calvino, poets Oskar Pastior, Jean Lescure and poet/mathematician Jacques Roubaud.
The group defines the term littérature potentielle as (rough translation): "the seeking of new structures and patterns which may be used by writers in any way they enjoy."
Constraints are used as a means of triggering ideas and inspiration, most notably Perec's "story-making machine", which he used in the construction of Life: A User's Manual. As well as established techniques, such as lipograms (Perec's novel A Void ) and palindromes, the group devises new techniques, often based on mathematical problems, such as the Knight's Tour of the chess-board and permutations.
What do they mean by “constrained writing techniques” exactly? Well, Perec’s novel A Void, for example, is a three hundred page book constructed entirely without the letter ‘e.’ I don’t know if I could write a blog post without the letter ‘e,’ let alone a whole freaking book. That’s pretty amazing. The question is, is it any good?
They also use other constraints like palindromes- the most famous of which is the old “Lisa Bonet ate no basil” line, which appears exactly the same whether you read it backwards or forwards. But they get much longer than that one.
I’d be interested in learning more about Oulipo. But while you consider whether or not to join me in my curiosity, take a look at the winners of this contest put on by the Outlet. The constraint they imposed was to write a story where no single word could be used more than once- not ‘and,’ not ‘the,’ not 'a,' not anything. Go ahead and read the winners. They’re all pretty short, but it’s interesting to see what people came back with. (Warning, some language in the first two- they seem to have been picked for their edginess. But the third is pretty impressive for its length and the story it tells.)