I think I recall you are planning one? If so, I love playing party planner so I can give my own suggestions since you are looking for a variety of answers! I haven't been to many but I do love party planning so please count me in!
Good weather: OUTDOOR settings are great. A nice private park or decorated courtyard setting are lovely. String lights are festive for evening settings.
GOOD FOOD and lots of it. I like catered styled events the best with tapas/small plates if you are able to pull that off. A real nice touch is if you can get some folks, family members or friends, to play hosts and serve on plates. Got a college age kid or family member? Get their hunky college buds to play hosts/waitors... smile... If not, a nice table spread with various dishes is lovely.. I LOVE a mix of world cuisines to chose from. It's always a culinary adventure! Fresh flowers are always a beautiful touch for table settings. Dessert? a layered cake with seasonal fruit filling generally is always a go getter. People really seem to look forward to cake at these kinds of events...
MUSIC! FOR SURE! Live music is even better! Maybe a son, daughter, family member, friend, church buddy, etc wants a small gig! Don't forget the option to barter for any "services"
Group games, crafts and a raffle - as Sue suggested - can be a blast. Another really fun group activity is some kind of instructional class where people can watch, learn and participate. Maybe a cooking or craft class taught by a friend or family membered skilled in that area. A "learn how to make..." instructional class about 30-45 mins/max so folks can stay focused and not get bored. DIY bath salts, aromatherapy, raw vegan food, seasonal foods/drinks, reflexology, accupressure, DIY handy home helpers/cleaners/beauty products, etc. are great ideas.
Before I continue, let me make sure you are even hosting one LOL or I may look a little foolish here LOL!!!
"Give a man a fish and you feed him for a day. Teach a man to fish and you feed him for a lifetime." ~Chinese Proverb~