If a girl...try temporary natural hair dyes for everyone. Movies, pizza (or favorite foods), maybe a dance-off contest with one of the dance games for whatever game system you may have. If she's into horses, find a stable that will let them ride or teach the girls. Ask her what she would like. Do it in a round about way though and get a couple of suggestions. This way she won't know for sure if you are trying to keep it a surprise. I wish I had some ideas for a boy for you. Good luck with your search.