"Dead Reckonings" has three solid adventures for Call of Cthulhu, all set in Lovecraft country. The adventures are fairly short, ranging from a one-shot to maybe a couple of sessions to finish. The adventures are complete, and all you need to play is a copy of the main "Call of Cthulhu" main book and a group of intrepid adventurers. The book has a separate hand-outs section in the back that you can photocopy or cut from directly.
The three adventures are:
Dust to Dust - Set in Martin's Beech, "Dust to Dust" is very loosely linked to Lovecraft's story "The Horror at Martin's Beach," and makes use of the Borellus' Resurrection Spell from "The Strange Case of Charles Dexter Ward." The scenario follows an insane cultist and his attempt to resurrect his wife. "Dust to Dust" is a one-shot adventure, that could possibly be stretched to two sessions depending on how deep you get into it. There is an option to connect this scenario to Kingsport: The City in the Mists and might be a nice lead-in to a longer campaign.
Dark Rivals - Set in Arkham in 1928, "Dark Rivals" deals with an occult war between a witch's coven and a gang of ghouls. This one isn't connected to any particular Lovecraft story. If you investigators like action, "Dark Rivals" presents a good opportunity to shoot some things that can actually be hurt by guns, although there is a surprise at the end so they shouldn't get too comfortable. This is also a one- or two-shot short adventure.
Behold the Mother - This is the longest adventure in "Dead Reckonings," and takes place in Arkham with the possibility of an excursion to Dunwich. Befitting a longer length, there is more actual investigation required during "Behold the Mother," and the stakes are higher. Unlike "Dust to Dust" and "Dark Rivals," odds are all of your investigators aren't going to survive "Behold the Mother," and definitely not with all of their sanity intact. If the name of the adventure isn't enough of a give-away, Shub-Niggurath might just show up.