Similar to the post about dropping pebbles, I have taken a bag of acorns with me before and purposely dropped one about every 2-3 minutes from my stand. I can't say for sure that the deer that appeared would have come in otherwise or not, but my feeling is that this helped bring them in.
It also doesn't hurt to be sitting in an oak tree at the time. I think the deer hear that sound and recognize the dinner bell. I can tell you that before I read this post I was planning that tactic for this Friday evening.
I also make a point of the acrons hitting leaves, etc, on the way down. I try to make it sound like a squirrel is high up in the tree cutting nuts and the deer will come over and begin nosing around right where they have been falling. I have never seen it spook deer yet and one time several years ago I was purposely dropping acorns on the back of a forkie that was right at the base of my tree. He showed no sign of alarm as I easily clonked him about 15 times. I was in greater danger of spooking him from my muffled laughter than from the many acorns bouncing off his back.