Spa Day

• Ask most women and they'll tell you this one's a no-brainer, but for some reason men just don't catch on. Your wife's gal pals, meanwhile, will commend you and be more than happy to participate. Call the best local spa in town--check the website of your city magazine for some suggestions, or else ask some of your wife's friends--and arrange for a full day of treatments for your wife and some of her friends. You don't have to go overboard--a half-hour massage, a facial, manicure and pedicure should do it. Drive your wife to the spa yourself, making sure her friends will be there first, and her surprise when she discovers where you are taking her will be compounded when she sees a gaggle of her friends there as well. Bring along a supply of magazines (fluff stuff like "People") so the girls can take a break from gabbing and just relax.
  
  The buildup: "Honey, I have a special surprise for you today. Just dress in something comfortable, and can you be ready, say, by 10?"
  
  

A Night on the Town

• Rent a party bus or extended limousine, pack it full of her friends and schedule it to arrive at your house just as you're about to leave for "dinner." Time it right and it will pull up just as you head out of the house. Hop in and take it to her favorite restaurant, or one she's talked about eating at for a long time, where you've made arrangements with the staff beforehand to reserve a large table, or even a room, with "Happy Birthday" balloons and flowers (caution: No "Happy 50th"). Afterward, hit at least one nightclub for some drinks and dancing--the beauty of this is no one has to worry about driving, since the bus or limo will deliver everyone back to their homes.
  
  The buildup: "I want to take you out to dinner for your birthday. Wear that beautiful new dress you picked out at Ooh-La-La."
  
  

House Party

• Don't throw this one at your house: Even if she doesn't catch on, there's bound to be some cleanup, and you don't want her to have to lift a finger. Arrange the use of a friend's home, preferably someone with a large "great room" or, if the weather's nice, a beautifully landscaped backyard, preferably with a pool. Serve a selection of fine cheeses, crackers and appetizers, along with some better wines. You're supposed to be grown up now, remember? Hire a deejay or pick up some CDs of music from when you and your wife were first married, or in college or high school; nostalgia is always big (how many husbands out there have seen their wives jump to their feet at the first sounds of Kool and the Gang's "Celebration"?). And for an extra special touch, write a little speech or poem about your wife that you can recite just before the deejay plays the song the two of you danced at during your wedding. (If your literary skills are so-so, try a professional service.)
  
  The buildup: "The Sandersons invited us over to their house for dinner to celebrate your birthday. They're good friends, so I figured that would be a nice way to celebrate your birthday."
  
  

Advance Work

• Three things to keep in mind before you start making plans for your wife's 50th birthday party:
  
  1) Does she even want a party? She might prefer dinner just with you, or just with you and the kids. Don't throw a big bash if she's not the partying kind.
  
  2) Invite the people she really likes--no one else. There's a certain point where a birthday party can become too big, and the focus is no longer on the birthday girl but on the party. Set limits--don't invite a bunch of your friends when you're wife either doesn't know or doesn't like most of them. Think of the people she talks to on the phone on a regular basis--those are generally a woman's closest companions.
  
  3) Be sneaky. Evites work best--everyone has email these days--or simply pick up the phone. Don't send our formal invitations with RSVP envelopes, but if you must, use your work rather than your home address.
  
  4) Buy her a tiara. Regardless of a woman's age, she always likes to feel special. And it sure beats a silly cardboard "Birthday Girl" hat.
  
  

If You've Got the Bucks...

• If you really want to go all out, tell you're wife you're going to fly her to dinner in San Francisco, or New Orleans, or New York--some town known for its fine dining that's close to you. Make reservations at her favorite restaurant, if she has one; if not, do some research online and find one just right for her. Make arrangements with a handful of close friends so that they arrive at the restaurant just before you do, and can help set up. This one's guaranteed--a surprise birthday party your wife will never, ever forget!