The magazine has some amazing yet simple party ideas all utilizing the famous poem. Online they highlight some of the ideas (click here) which includes links to raven artwork, menus, and stencils. Additionally, there are extra ideas exclusively online (click here) that are different from the publication. This would be a fun party and guests could dress the part with black feathered masks etc.
Alternately, a gothic theme can be fun. Check out these ideas for a Ghoulish Gothic Party (click here) that also includes recipes. You could even combine this with the Raven theme too. This one would be perfect for Munsters or Adams Family costumes! These provide ideas galore to spur your own creativity.
There are sewing patterns as well if you are good at sewing.
Or perhaps you are more the Fall Harvest Party type of person. Here are some ideas to help you out too (click here) and also (here too).
A word of caution, please keep your cats (especially black cats) inside around October 31. It is sad to say, but they are often snatched and horribly hurt by demented people this time of year.
Here is a way to make your own Morticia costume from scratch creating your own pattern.