The acronym means Ouvroir de Littérature Potentielle (Workshop for Potential Literature), a group of mathematicians and writers formed in France in 1960. The group rejected spontaneity and the subconscious within literature, suggesting instead that greater creativity stems from systematic, self-restricting texts. It's aim was to 'free' literature by tightening its rules. Basically, the idea is if you place numerous rules upon your writing, then you can create a whole new literature.
This literary collective may seem slightly bizarre but it is worth considering what they say, for they do not claim to know what literature is, but hope to uncover what it might be. This Guardian article calls it the equivalent of literary bondage. The claim is that writing is always constrained by something, be it time, language or talent. We don't need a big discussion of it here, but instead perhaps can pick out aspects which are of use to fledgeling and other writers. Here's a brief guide.
Oulipians are rats who build the labyrinth from which they will try to escape.
— Raymond Queneau, Oulipo cofounder
Interestingly, when we discuss writer's block and ways through it, we tend towards free writing, distraction techniques, looking for prompts, etc. However, the founders of Oulipo created exercises to place certain restrictions on writing. For example, they wrote entire pieces without a certain letter, or chose words in a work to replace with other words based on a specific formula. My writing group tried this once, writing with the letter e.
If you are struggling to write, why not have a play with words? Here are a few examples.
Or watch this rendition of a popular Pulp song.