What about a snack type/food related kit? Like a hot chocolate kit, italian foods kit, cheese/sausage kit or a make your own comfort foods kit that contains maybe fudge, cookie mix in a jar, some recipes, cookie cutters, etc. all in a basket. Seems fun for kids to me and you could always adjust the food items to be more gender neutral - nuts, drink mix, candy/treats, cheese/sausage.
That seems the most neutral for gender and age to me.
Or they have those soup versions at Wal-mart I've seen before as well. :)