Half-Life 2's gravity gun has been insanely influential to video games as a whole. Even though we've been waiting for a sequel to the game for what seems like forever, we've seen hints of greatness in games from Portal to Dead Space that incorporate physics engines made popular in Valve's iconic series.
If you're a fan of the series or manipulating gravity generally, then you should stop what you're doing and watch Corridor Digital's 5-minute video inspired by Half-Life 2's weapon. This was made for YouTube's Geek Week (which is unfortunately now over). The video features heroine Alyx using the gravity gun and ultimately having an insane showdown, upside down on a bridge. Check it out: