If the new year struck you with desire for a romantic comedy about friends with benefits -- and you're over 17 -- you have two to choose from in 2011: No Strings Attached and Friends With Benefits.  No Strings Attached stars Ashton Kutcher and Natalie Portman and has the jump on Friends with a January 21st release date.  But the Justin Timberlake/Mila Kunis-led Friends With Benefits introduced itself with a red band trailer that effectively announced: "Don't fill up too fast.  I'll be ready on July 22nd."Not to be outdone, Paramount has followed up on the all-ages trailer released in November with a raunchy red band trailer for No Strings Attached, which you can watch after the break.Via Cinema Blend -- be warned of NSFW language and a closeup on Kutcher's naked butt:I'm not much of a Kutcher fan, and his line readings here are grating.  But there's plenty to like.  Goofy Portman.  Ludacris and Mindy Kailing as the best friends.  "You look like a pumpkin, bitch."  Still not completely sold, but getting there.Ivan Reitman directs from a script by Elizabeth Merriweather.  Here's the official synopsis:

In this comedy, Emma (Natalie Portman) and Adam (Ashton Kutcher) are life-long friends who almost ruin everything by having sex one morning. In order to protect their friendship, they make a pact to keep their relationship strictly "no strings attached." "No strings" means no jealousy, no expectations, no fighting, no flowers, no baby voices. It means they can do whatever they want, whenever they want, in whatever public place they want, as long as they don't fall in love. The questions become - Can you have sex without love getting in the way? And can their friendship survive?