• Turning 40 is a major life milestone and deserves to be celebrated. Some people will choose to have wild parties; others, a quiet evening out. The best celebrations are always those that reflect the personality of the birthday boy or girl.
  
  

Surprise Party

• Almost nothing is more flattering than friends and loved ones planning a birthday surprise, and this effect can be doubled if the list of guests includes people the birthday boy wasn't expecting to see, like a sibling who lives across the country or a college roommate who's fallen out of touch. These kinds of parties are a great opportunity to let people know just how special they really are. Make a large bulletin board and ask party guests ahead of time to bring something they can post to show their favorite memories of the person being celebrated; or create a photo-retrospective of that person's life.
  
  

Weekend Getaway

• According to the London Times, people are staying active later and later into middle age. Remind the birthday girl that turning 40 doesn't mean getting old by letting her relive her younger days. Go backpacking, or road tripping or to a weekend rock festival. Depending on the nature of the festivities, it might be best to leave the kids at home.
  
  

Dinner Party

• Surprise parties and raucous weekends aren't for everyone. Some people don't like calling attention to their birthdays, and others are just quiet types. Help them celebrate by throwing a quiet but impeccably organized dinner party at home. Invite old and new friends to create an environment ripe for storytelling and reminiscing. And maybe even inject some zest into the proceedings by theming the party after the year the birthday boy was born. Guests are sure to get a kick out of sampling the taste and look of forty years ago.
  
  

Games

• From the most intimate dinner to the biggest surprise birthday bash, any party can be enlivened by games. Try to develop these games around the personality of the birthday girl----and around the theme of turning 40. A boisterous, good-natured birthday girl might appreciate a birthday roast. Friends put together a list like, "40 Surefire Ways to Know Your With Jill" or "Jill's Top 40," which would be like the "Top 10" lists on David Letterman's show. Birthday girls less likely to be receptive to a good needling might prefer a Karaoke machine supplied only with the top selling single from each of the 40 years of their life.