Volvo (yes, the car manufacturer) just released a luminous paint that's invisible during the day and then brightly fluorescent at night as soon as car headlights bounce off it. The paint is safe to use on medal, wood, plastics, fabrics, shoes, and even your skin.
You can spray it on your bike, helmet, clothing or shoes to make sure you light up the night during your nighttime rides or runs. As someone who rides a bide to work every day, desperately attempting to do everything in my power to not get it by a car when I am cycling home at night after a long day, this paint is pretty intriguing.
There is some things to note. The paint is not permanent, Volvo states that it will come off in about 10 days. This makes it good in some instances and not so great in others. If you don't want to have to keep buying a can of paint every few weeks so you can keep your bike glowing, maybe think about spraying a clear coat on top of the fluorescent paint. But if you don't want your clothes lighting up in the night all the time, all you need to do is wash them!