I never got into the original books, but I’m a fan of what others have done with them since.
Not familiar with the mythos? HowStuffWorks explains.
Neil Gaiman has a couple stories up for free. (A Study in Emerald is particularly good if you’re at all familiar with Sherlock Holmes.)
Hello Cthulhu mashes up Lovecraft and Hello Kitty.
Cthulhu has run for President.
The H. P. Lovecraft Historical Society keeps the flame alive, including themed holiday albums.
There’s also the HPPodcast, which I’ve yet to give a proper listen to.
And, like every other celebrity, he’s taken a turn at being a talkshow host.