As your sister turns the big 5-0, give her a gift that recalls fond memories and show her how special she is to you. This milestone of a birthday may have you wanting to buy an “over-the-hill" gag gift, but before you do, you might want to have a thoughtful back up plan. Remember that some women are sensitive about aging, so choose a birthday gift she will treasure.

A photo book that showcases your sister’s life from infancy to today will surely be appreciated. You can scour the old albums in the attic as you select pictures to be touched up, such as her as a baby in the bubble bath, the first school dance, a birthday or Christmas photograph of you both. Add her wedding pictures, her children's photos and her vow renewal pictures to the book as you fill it with funny comments and serious thoughts. Consider scanning in old report cards, slices of a journal or cards she has kept as a memento of years past.

By now, you should know whether your sister’s jewelry style is flamboyant with one big stone or conservative with small stones tastefully set, Buy her a signature piece to add to her collection depicting her sense of style, as you decide on a set of earrings, several bangle bracelets, a pendant set on a chain or a strand of pearls for special occasions. You can hide the piece in a wooden jewelry box that plays her favorite song.

Share the day with your sister by showing up at her office with a bouquet of her favorite flowers and treating her to lunch or whisking her away for a weekend trip to a city she enjoys, like San Francisco, New Orleans or Las Vegas. Consider purchasing tickets to a mystery dinner theater, a comedy show or a play for the two of you to share. Or buy her season pass to the opera, theater or favorite sporting event. A gym membership or yoga class that will help keep her in the same sexy shape she is in now will be appreciated.

Set up a "Remember When" birthday page for your sister on Facebook or a website such as webs.com. Contact her old school and college chums through the school's alumni center, while you contact former co-worker friends through previous employers. Ask them, family and current friends to leave birthday wishes at the site and share their favorite experiences with your sister. Ask people to email photographs or video to add to the site. Surprise her on the day of her 50th birthday with a link to the site celebrating her first 50 years. This is a gift she will treasure.

You can add a piece to your sister's existing collection or choose items from her favorite artists, DVDs or books as a gift. Perfumes, a designer bag or shoes, accessories like belts or brooches would also be a thoughtful gift.