The person who will bring us upcoming Star Trek and Star Wars: Episode VII a.k.a. director J.J. Abrams is already in talks with the Video Game Publisher Valve for movies based on Portal and Half-Life. On the note he stated that he is personally interested in creating those movies and the talks with the publishers are also on yet in early stages.
“And both a Portal and Half-Life movie are things I want to see.We’re also aware of the cautionary tales of movies that became games and vice versa. Our goal here to is to treat the world Valve has created in both these properties like anyone would a book or some great story that comes from a pitch or original script — just to treat it with the respect they treat their games and their players with.”" , Abrams said
Probably people might know that way back in 2010 Valve co-founder and president Gabe Newell expressed his idea about creating movie based on Half-Life. In addition to that both J.J. Abrams and Newell are in talks for collaborating for a video game. So this gets surely for real.