We are not planning on doing gifts as of right now, but if I choose to I will leave it with the best man since we will not be getting ready in the same place. I am however getting him a charm (I have a matching one in my bouquet) and a letter from me to slip into the pocket of his suit so he wont know its there until he puts it on. I would do it in the morning.
My husband surprised me with a letter and sent it into my bridal suite (while I was getting ready) through our coordinator. Our photographer was there to snap pics. Part of our ceremony was love letters we had each written to the other being put into a box with a bottle of wine to open, read and enjoy on our fifth anniversary (or sooner if we need a reminder of our love).