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 . May 20, · 14 Best Theme Party Ideas For Adults kucks.xyz party Inspired from the romantic movie, ‘Animal House’, toga party is the most classic adult theme party idea. .