Cover your trampoline springs with pool noodles. I was pinched in springs so often when I was a kid. This is safe and looks awesome. Now I just need a house with a garden to put my pool-noodled trampoline in.
DIY busy board full of switches, latches, and doo-dads for babies and toddlers to manipulate. This is great for fine motor skills. It is also a hazard for giving escapee toddlers the skills they need to get out unsupervised.
Write a letter to your child or grandchild each year and include money for grad gift. I like this idea of writing a letter, and even adding money, but I think it'd be better to go longer than a grad gift. Wedding, first home, first child?