Select a future age for your birthday boy/girl, and ask all the guests to write a letter to him or her at that age. Provide colored paper, tractor and farm animal stickers, envelopes and pens. You can salvage a shoebox or popcorn tin to use as the time capsule. Put all letters, as well as the day's newspaper clippings with dates and some photos from the party, in the time capsule and seal it up, to be opened at a birthday party years in the future. The nostalgic feeling is bound to touch his or her heart.