My job is very demanding and I put a ton of hours in. For me, and those like me, the biggest sacrifice I could make would be to spend some time with someone who is lonely, or in need of a friend.
Leave the BlackBerry or phone behind, don’t wear a watch, and plan nothing for a good few hours and let someone know that you care enough to give them something money can’t buy.

Cheesy, but having been that person in the past, and now seeing the other side of the coin, I know it would be a huge present to someone.