Plot summary

The movie opens with a voiceover by Jane (Katherine Heigl) as she explains when she first discovered her "calling" in life. The scene is from her childhood when she, her younger sister Tess and their father attend a realtive's wedding. This is shortly following the death of their mother so Jane must act as a mother figure for her sister. When her father asks Jane to take Tess to the bathroom, she comes across a distraught bride who has torn a seam on her dress leaving a whole at the back of the bodice that shows the upper half of her rear end. Jane has a moment of epiphany and uses her sister's hair ribbon and sews up the back fo the dress in a becoming way. The ecstatic bride then asks Jane to carry her train down the aisle as a reward.Flash forward in time to the present -- Jane is in a bridal shop with seamstresses all around her hemming a wedding dress. A woman walks in and says "The bride is on the phone" where you discover that Jane is the same size as the bride and is doing her bridesmaid duty of having the wedding dress hemmed the morning of the wedding for the panicking bride. She leaves the store, dress in hand, wearing her bridesmaid dress and hurries to the nuptials making it in time for the bride to change and get ready for her ceremony.During the ceremony, Jane continuously looks at her watch and a guest at the wedding (played by James Marsden) notices her impatience. As soon as there is a break in the festivities, Jane rushes out and hails a taxi whose driver she offers $300 for the entire night if he agrees not to look in the rearview mirror or he will suffer a deduction from that sum. Jane proceeds to change into another dress which is revealed as a traditional Indian sari that is her bridesmaid's dress for another wedding on the same night. Throughout the remainder of the night, she speeds between weddings/receptions, changing in the taxi which is seen by Kevin (James Marsden).At the end of the night, Jane is at the first wedding preparing for the bouquet toss which comes straight for her until she is tackled by some over-enthusiastic girls and knocked unconcscious. When she wakes up, Kevin (James Marsden) is leaning over her and helps her up, where she swoons, and then offers to accompany her home.On the trip to Jane's apartment, Kevin comments on her two-wedding night and proceeds to mention his opinion about the ludicrousness of the ceremony. This sparks a lively debate between the two about the sacredness of a wedding and marriage which leaves Kevin charmed and Jane annoyed. Once they reach Jane's apartment building, she leaves and Kevin discovers her "filofax", or day planner, in the taxi and decides to look through it.Kevin Doyle (James Marsden) discovers that Jane has been in 7 weddings that year and, as he is the writer of the local newpaper's "Commitments" section (under his full name Malcolm Doyle) he asks his editor if he could write a feature story on Jane (Heigl) for the front page of the section in the hopes that, if it is good enough, he can get out of the "taffeta ghetto."The next scene, we see Jane going to the office with her friend, Casey (Judy Greer), who was also in one of the weddings with her. Once inside the office, Jane is heckled for her longtime crush on her boss, George (Edward Burns), to whom she is a personal assistant. Everyone knows about her infatuation except for George, who owns the eco-friendly outdoor sports magazine business that they work for. Flowers are delivered for Jane without a note and she excitedly assumes that they are from George. When she leaves work with Casey (Judy Greer), Jane says that she has to go and pick up her sister from the airport but that she will see Casey later at another coworker's engagement party that night.At the airport, Jane picks up her sister, Tess (Malin Akerman) who has been working in Milan as a model. They go back to Jane's apartment, where Tess will be staying for a few weeks, and they talk about their parent's wedding photo which Jane has framed in her house. They agree that it was romantic but Tess dislikes her mother's dress while Jane is completely taken with the entire event -- at the boat house, at sunset, etc. Tess proceeds to pick up a pile of newspaper clippings on the counter that are featured engagement profiles from the paper