Just get a bunch of empty boxes. Wrap them up in pretty, colorful bows and extravagant looking wrapping paper. Then go to Wal*Mart and buy a disposable camera. Try something with 800 film speed since you'll be inside of a dark room where the only light will probably be from the candles of the cake. Next get a BIG teddy bear, this should be the only real gift you get him. Also remember to get a Happy Birthday card and place all your cash into it. Then have a friend or relative snap losts of pictures of you, the birthday boy, the teddy bear, the card LOADED with money and the fake presents. Then take back the money in the card and go to Longs and develop the pictures.
Fifteen years from now show your nephew those pictures and tell him that NO ONE was ever as generous to him as you were to him. He'll always love his giving uncle.