Cthulhu games are a dime a dozen these days, with everything from JRPG parodies to well-meaning but flawed efforts that bear the official Call of Cthulhu license. But there aren't many point and click adventures showcasing H.P. Lovecraft's sanity-twisting mythos. Two very dated Infogrames efforts in the early 90s come to mind, but if you haven't played 1993's Shadow of the Comet and 1995's Prisoner of Ice, you're not missing much.
The Dark Rites of Arkham, by indie developer Postmodern Adventures, rectifies this with a well-rounded effort filled with odes to all of Lovecraft's best stories. It has the quality of a Call of Cthulhu tabletop campaign assembled by a well-read fan.