Humans are built to multi-task—we've got crazy amounts of energy and vast brain capacity. But one of the hazards of living in a modern economy is being pigeonholed into roles that only engage one or two of our talents and a handful of our skills. Don't let your professional job (or an overbearing boss) prohibit you from going out on your own and exploring your potential in other fields. Start a side project that will not only develop the expertise neglected by your day job, but will also enrich your life and diversity your resume. Starting a side project allows you to be your own boss, self-manage, and foster your creativity. And you'll soon find that the benefits will overflow into your professional career.