Christian Philipp Muller works in different media with themes of site and location.
Most interesting to me of his works are his illegal border crossings, one of which he submitted for the Austrian Biennale. Illegal Border Crossing between Austria and Czechoslovakia simultaneously engages art-world discourses on the site-specificity and global issues of migration and privilege.
In a similar social vein is Jens Haaning broadcasting funny stories in Turkish through a loudspeaker in a Copenhagen square. Turkish Jokes addresses the multiplicity of publics that experience a public work, and themes of immigrant community/alienation.
Mierle Laderman Ukeles' 1973 "Maintance Art" series intervention art which address feminist, class, and labor issues.
"In two performances, Ukeles, literally on her hands and knees... scrubbed the floors inside the exhibition galleries... In doing so, she forced the menial domestic tasks usually associated with women--cleaning, washing, dusting, and tidying--to the level of aesthetic contemplation, and revealed the extent to which the museum's pristine self-presentation, its perfectly immaculate white spaces emblematic of its 'neutrality,' is structurally dependent on the hidden and devalued labor of daily maintenance and upkeep... Ukles posed the museum as a hierarchical system of labor relations and complicated the social and gendered divisions between the notions of the public and private (Miwon Kwon)."
In 1983 she created The Social Mirror, a sanitation truck faced in mirrored glass. As it drove around, it reflected city dwellers' images back at them.
The Yes Men I love, and admire for their works' humor in dealing with serious and troubling issues of globalization, which makes them hugely appealing and garners them media attention in the pseudo-event tradition of Abby Hoffman.