Throwing an adult Halloween party is easier than you think, as you can go overboard gory or keep the blood and guts to a minimum for squeamish people. To throw an adult Halloween party, you need: Creepy invitations Freak-show karaoke  A suitable Halloween theme (super gory or funky, for example) Ghoulish snacks and punch Age-appropriate Halloween games such as bobbing for rotten apples in a bucket of punch