An artist-run initiative is any project run by artists, including sound or visual artists, to present their and others' projects. They might approximate a traditional art gallery space in appearance or function, or they may take a markedly different approach, limited only by the artist's understanding of the term. "Artist-run initiatives" is an umbrella name for many types of artist-generated activity.
One such group, the Belfast-based Catalyst Arts, wrote that:
"Artist-run means initiating exchange; emphasizing cross and inter-disciplinary approaches to making art; developing networks; through curation, putting creative ideas and arguments into action" 
Important historical artist-run initiatives include the North Edmonton Sculpture Workshop in Canada, The Wrong Gallery (using a disused doorway to display work) in New York City in the 2000s, and City Racing (an old betting shop) in London in the 1990s. Damien Hirst's one-off exhibition Freeze in a London warehouse in the 1990s could also be said to be a temporary, yet important, artist-run initiative. Artist-run initiatives have used cars, briefcases, and other unusual exhibition venues where traditional spaces were too expensive or limited. Cuckoo is a New Zealand-based artist-run initiative where its members use other people's spaces to present their program, like a cuckoo bird does by placing its own eggs discreetly into the nests of other birds.
Artist-run initiatives also play a role in hosting international artists: they may also include guest studios or even international artist in residence programs.