What's the most fun way to learn music theory?

I've been playing piano for years, but always hated music theory, since I like to envision soothing imaginings while I play and not be distracted by repetitive little notes and latin words. I want very much to master music theory for many reasons, but without the sense of restriction and drudgery. Has anybody felt similarly and overcome it, now loving and liberated by music theory? Any books, software, techniques you can recommend for this?