Well, she could go to the party as a witch. When she arrives at the party, she notices that there is a costume contest. She decides to enter. She shows off her broomstick prop and her magical - looking hat. As she mingles with the other party - goers, she uses her 'witchy' charm to make everyone laugh. She ends up not winning the contest but has a great time regardless, making memories with friends and strangers alike.
One possible story could be that the wife goes to the Halloween party dressed as a fairy. At the party, she meets an old friend she hasn't seen in years. They catch up, share some spooky stories, and dance to the eerie music. Then they enjoy some delicious Halloween - themed treats like pumpkin - shaped cookies.