If you can't do that, you could do a masquerade ball.
Or (if you're interested in this) you could do a vintage Hollywood party. Have people dress up as famous old Hollywood actors/actresses. Marilyn Monroe, Audrey Hepburn, Bette Davis, Vincent Price, James Dean, etc.
Try looking up ideas on pinterest.
Its my birthday in February and I don't want anything big I was just thinking about 20 of my closest friends over for a dinner party.
Although I don't want it to be totally lame and boring so I want it to have a theme.. for example last year I did the Mad Hatters Tea party which was so fun as everyone had a character from Alice in Wonderland to dress up as and all the food and table was all quirky.
So im looking for a similar kind of idea? maybe a murder mystery... if anyone has any suggestions it would be a great help!
Thanks