Tulips, hydrangea, lilacs, and other flowers offer a sweet feminine touch for your event. Go for an adult theme party that's bold and exciting with fiesta decor, spooky soiree supplies, a sun and sand theme, luau, or western party. Some other party themes for adults to try include rock and roll, casino, movie night, or mustache party. Jan 16, - Explore Parties | Party Ideas's board "Adult Party Themes", followed by people on Pinterest. See more ideas about adult party themes, party, party themes pins.