Two Girls and a Guy (1997).

The Scoop:
The two women (Heather Graham and Natasha Gregson Wagner) in a love triangle find out about each other and confront their mutual boyfriend (Robert Downey, Jr.), forcing him to be honest for once in his life.

Although writer/director James Toback delivers a very stagey production (the material would work much better as a play than a film), the acting of all three leads is top-notch (even from the often spotty Wagner) and fascinating to watch. In fact, this whole movie is an actor's dream, offering these three several opportunities to show off their chops -- particularly Downey, who is a natural as the weasely prick. Most of the dialogue was improvised and, while it may not offer the most edge-of-your-seat entertainment (although there is a great sex scene), watching this provides a great workshop in the craft of acting, and a few insights into romantic relationships as well.

Best Line:
"Hey Blake, do you want to braid Carla's hair with me?"

Side Note:
Downey shot this during weekend furloughs while serving one of his many jail stints for drug charges.

Companion Viewing:
"Reservoir Dogs" (1992).

Links:
IMDb.
The official site, which still exists a full decade after the film was released.

Take a Look:
The trailer is available at IMDb.

And here's a tease from the sex scene: