My family and I use the 'Find My Friends' iPhone app pretty regularly. At a glance and without bothering each other, we can figure out where we're all at to coordinate. I can see if my wife's at the gym, she can see if I'm still at the office, I can see if my daughter's at a friend's house like she claimed to be, etc.

When there's an occasion where I don't want people to know where I'm at, like when I'm shopping for Christmas or birthday gifts, I just stop sharing my location temporarily.