My girlfriend pushed me into airsoft after I was introduced to the concept by the local group, now she pushes me to continue, and uses the excuse of exercise. Plus she's really big into a few WW2 FPS games, and her and I play a lot of that together. Not so big on the running in a field part, but can name most of the guns on display at the local airsoft store without issue.
My parents know, but that's about it. I'm not sure if they understand what it is, I will have to show them sometime when I can get them over.
Most of my friends are like me, and while they may not play, they're not surprised or anything. The GM of my work (Security, including Armed Security) thought it was silly until I whooped some of the skilled armed guards in simmunition training, now he wants to start a company team for "under-pressure training".