The movie No Strings Attached is about two people, who were friends when they were younger, and continue to run into eacher other as they get older.  Eventually they decide to have a "No Strings Attached" relationship, where they will just sleep with eachother and be friendly, but not have any emotional or romantic connections.  In the end they realize that their relationship has changed because of how much time they spend together, the end up falling in love.
   
   Infatuating love from Sternberg's Triangular Theory of Love is one theory that explains the relationship in this movie.  The couple has a lot of passion, but they decidedly plan to not have commitment, which is the no strings attatched part.  There is also little intimacy.  At one point after they hook up, Ashton Kutcher's character snuggles, but Natalie Portmans character says she thinks they shouldn't do that.  So there is definintely no intimacy allowed. 
  
   Ludus from Lee's Styles of Love also applies to the couple.  This specific relationship is very playful in nature and involves little commitment.  Also, at one point in the movie, the girl character thinks there is too much intimacy/attachment developing between them, so she tells the guy to go sleep with other girls.  This relates to the point that in ludus there may be multiple partners.