The film opens with Nora studying law and Mary shopping. They head to their home, Casa Bonita, for their father's birthday. While dancing with their father, he collapses and dies.
Jeff Peters (John Malkovich) is an emotionally repressed scientist who can't stand others because of their intellectual inferiority. He dreams of deep space exploration, which would be difficult because of the lack of human contact for long periods of time. He develops the Ulysses android (which looks exactly like him) for the purpose of space exploration, since an android would not be affected by the isolation.
E.J. Baxter (Kristin Chenoweth) is a headstrong and popular New York City publicist. E.J. seemingly has the "perfect life"; a beautiful condo, a loving fiancé, a great job, and an excellent boss. But E.J.'s world takes a turn for the worse when she catches her fiancé Noah having an affair with her boss Lillah at the office Christmas party, resulting in E.J. breaking Lillah's expensive Gucci pump shoe, and breaking off her engagement with Noah.
The film opens with Carla Bennett (Heather Graham) and Lou (Natasha Gregson Wagner) waiting in front of a New York building where their boyfriends live. In conversing, they find out Blake Allen (Robert Downey, Jr.) is their duplicitous boyfriend. In the first minutes of the film Blake is revealed to be a narcissistic actor, dating both of them on the side while claiming to visit his ill mother on the other days. The women wait for Blake inside his loft and confront him together. The remainder of the film takes place inside the loft, where Blake tries to talk his way out of trouble. In the end, both girls reveal that they have been unfaithful. Carla and Blake have sex, but Lou's suggestion of a threesome is rejected. His mother dies at the end of the film and Carla comforts him.
Seenu (Varun Sandesh) is going for his second marriage and he meets Nimisha (Nisha Shah). Avantika (Nisha Aggarwal) is also going for her second marriage and meets Yuva (Shashank). Both of them decide to tell their partners about their past. The flashback reveals how Seenu and Avantika meet each other, fall in love, get married against their parents wishes and in no time, get separated as well. Now, the time comes when they are almost about to get married to their new partners. All the four want to break their marriages and break them on the day of marriage. Seenu and Avantika Break their Respective Marriages with the consent of their new partners and reconcile to lead a happy life together.
Dodò (Francesco Casale) is a Roman university lecturer who is of ripe age and prominent standing but his life is still under the mandate of his father Alberto (Franco Branciaroli), a retired professor and mature womaniser currently bedridden due to a fracture and living with his nurse Fausta (Cristina Garavaglia). His relationship with his father is further traumatised by Dodò's affliction for his deceased mother. Dodò is married to voluptuous Silvia (Katarzyna Kozaczyk as Katarina Vasilissa), a former student of Alberto but, one day, Silvia leaves Dodò with no obvious reason. Dodò indulges his sexual urges with getting deeper in his obsessive voyeurism. Soon, Silvia comes up with the confession of having an affair with another man. Silvia contrasts Dodò's sentimentalism with her illicit lover's raw sexuality and Dodò starts to think that the other man is actually his father Alberto.
Karan(Shahid Kapoor) is a shy and nerdy canteen boy and college student, running a café with his friend Murugan (Johnny Lever), and Tanya (Rimi Sen) is a student in the same college. She is the most popular girl on campus. Karan is in love with Tanya but is too shy to tell her. After he musters some courage and rescues her step brother from some goons, he catches her attention and his eventually able to invite her for a fake birthday party. On her way there, Tanya witnesses the murder of a scientist, Khurana (Om Puri) by his evil twin brother, the underworld don Mehboob, and as a result is forced to flee the country to save her own life, since the law had been bought over by the very same killers. The scientist had stored a secret code in a stuffed toy, a parrot, now being sought by Mehboob, and he had been able to hide the toy in Tanya's car before being killed. Unawares, Tanya leaves the toy at home before fleeing the country, and the toy is later picked up by Karan, who himself is not aware of Tanya's predicament.
Frustrated with the fact that he cannot give his wife Priscilla (Parker Posey) an orgasm, Jack (Paul Rudd) moves out of the house and starts a relationship with Kristen (Mischa Barton), his student. Unfulfilled, Priscilla forms an unlikely partnership with Wayne (Danny DeVito), a businessman more than twice her age.
Richard Babson and Paula McCullen are a couple of Hollywood screenwriters who have lived and worked together for a number of years. Richard would like to get married, but Paula does not feel the need.
Luke Wilson appears as good-hearted ex-con Wendell Baker working in a retirement home, with Luke's other brother, Owen Wilson, as the home's head nurse. Eva Mendes co-stars as Luke Wilson's character's love-interest, Doreen. Baker, along with three residents of the home, help him win Doreen back; and, Baker helps them fight the corrupt staff. The film also features Eddie Griffin, Kris Kristofferson, Harry Dean Stanton, Seymour Cassel and Will Ferrell.
Helen MacFarquhar (Kate Capshaw), a middle-aged bookseller, having recently divorced and after sending her daughter off to summer camp, and her nagging ex-husband trying to convince her to pay for some of their daughter's activities is ready to move on to the next stage in her life. One morning, as she is going through the mail, she discovers an anonymous blue love letter, without an envelope and a name. Having discovered this letter in her mail, in her bookstore, she naturally thinks it is for her. But the only question is, who is it from? At first, she thinks it is from George Matthias, the local fireman, but decides it couldn't be him, after trying to give him subtle hints ("have you ever been 'on fire?'") Not having any idea who may be the writer of the love letter, she just puts it away in her purse and tries to forget about it.