Slavoj Zizek is one of the major figures, but it's difficult to know where to start with his huge output of books. So here's a starting point: John Gray writes about the famous leftist theorist in the NYRB:
Here's a more sympathetic view in the LA review of books.
There may be some who are tempted to condemn Žižek as a philosopher of irrationalism whose praise of violence is more reminiscent of the far right than the radical left. His writings are often offensive and at times (as when he writes of Hitler being present “in the Jew”) obscene. There is a mocking frivolity in Žižek’s paeans to terror that recalls the Italian Futurist and ultra-nationalist Gabriele D’Annunzio and the Fascist (and later Maoist) fellow traveler Curzio Malaparte more than any thinker in the Marxian tradition. But there is another reading of Žižek, which may be more plausible, in which he is no more an epigone of the right than he is a disciple of Marx or Lenin.
Whether or not Marx’s vision of communism is “the inherent capitalist fantasy,” Žižek’s vision—which apart from rejecting earlier conceptions lacks any definite content—is well adapted to an economy based on the continuous production of novel commodities and experiences, each supposed to be different from any that has gone before. With the prevailing capitalist order aware that it is in trouble but unable to conceive of practicable alternatives, Žižek’s formless radicalism is ideally suited to a culture transfixed by the spectacle of its own fragility. That there should be this isomorphism between Žižek’s thinking and contemporary capitalism is not surprising. After all, it is only an economy of the kind that exists today that could produce a thinker such as Žižek. The role of global public intellectual Žižek performs has emerged along with a media apparatus and a culture of celebrity that are integral to the current model of capitalist expansion.
Žižek will frequently present what he views as a commonly accepted belief, then turn around and ask, “But is not the exact opposite the case?!” And then, as one continues reading, it often begins to seem as though the forcefully asserted opposite view is not quite Žižek’s own; it too gets called into question, with the surprising result that the first naïve view begins to look somehow less naïve.
I'll read one of his books at some point, probably Less than Nothing.
The initial reversal can sometimes look alarmingly like a cheap, Christopher Hitchens-style contrarianism, particularly since Žižek’s political writings often start with a mainstream liberal view and then assert one that sounds much more right-wing. Yet the point is not simply to “provoke” liberals or to play devil’s advocate. Rather, these reversals are part of a strategy to keep the thought in motion. Instead of proposing a solution or finding a resting place, Žižek relentlessly seeks out further conflicts and contradictions, carrying out what Marx called “the ruthless criticism of everything existing.” The goal is not to arrive at a settled view, but to achieve greater clarity about what is really at issue, about what is really at stake in a given debate.