I don't think any concept from a video game has impacted my daily thought processes as much as the Translocator from Unreal Tournament. Basically the Translocator is a Frisbee launcher with a button that lets you teleport to the spot where your Frisbee is. So, if you want to get upstairs in a hurry, you shoot a little disc upstairs over the railing, hope it landed in a safe spot, and then you activate the transportation effect. If you happen to position the disc underneath someone else and then activate it, you'll be teleported inside that other person and they'll just sort of explode in a shower of guts. If you fired the disc off into orbit and then activate it, well then you're probably going to suffocate in space.
In real life it would be a tad dangerous to use terribly often (as illustrated by the number of accidental suicides and homicides that it causes in the game), but it sure would be convenient. Hardly a day has gone by in the past decade that I haven't thought of firing a disc off to some distant spot and teleporting there instead of waiting for an elevator or slow-moving people on the stairs. (I don't usually think of the murder features all that often, but depending on the situation I suppose they could be a potential added bonus.)