Speakeasy, Great Gatsby or Downton Abbey
There are plenty of online clothing suppliers such as Unique Vintage selling stunning flapper dresses for very reasonable prices.
The options are limitless but if you are going for Speakeasy set up spy hole in the door and make sure all guests know the secret password. You need to set up a card table and better have a good supply of “HOOCH”. Where as Gatsby has be martinis while Downton Abbey would be gin or a Pims – and you are going to need a butler and some footmen.
Grab a silent movie – there are plenty free online and maybe use a PC projector to have it running on a wall.
There is a company called Gramovox who sell a bluetooth gramophone