The history: as a young and ignorant female I was on my way to a theater rehearsal at my local high school. I was riding my bicycle. It was late in the evening and winter. I was hurtling down a steep hill. At the bottom was a green light. I arrived at the intersection just in time to be struck by a car making a right turn, the classic right hook. I should not have been passing cars on my left like that, I should definitely have had some lights on my bicycle as it was well after sundown. I was thrown off my bicycle and briefly knocked out. The car drove away. A person stopped and helped me out of the road and brought me my newly arranged bicycle. I walked the rest of the way. Someone I knew twisted my bicycle back together and I rode home after the rehearsal.
More history: Sometime after college I worked out that I needed bicycle lights. These reflector things were...insufficient. I went to a bicycle store and looked at the prices for the lights. I found that I could afford one light. I bought one red tail light.
Fast forward to the present: Night has fallen on us, my friends, and there are many bicyclists out there with no lights. Maybe they're too poor to have lights. Maybe they're too stupid. Maybe they almost never ride at night and so they did not think it was worth buying one. Maybe their batteries are dead and they keep forgetting to get new batteries.
What you do: buy a set of bicycle lights. If you drive a car buy two sets of lights and put one set in your glove compartment. When you see a bicyclist without lights in the dark, catch up to them and say "o hai! I noticed you have no lights and I happen to have a set I would like to give to you." Fish the lights out and hand them over. Do not be critical. Do not use bad language or be superior or unkind in any way. Appreciate the bicyclist for being out on the road and making your life fractionally better by reminding the cars that they need to watch for us.
What you do NOT do: Do not steal the lights off the bicycle of the cute girl/boy at work and then chase the person home and say "hey, I have some lights for you, also can I get your number?" That's stalking.
What not to say: "Bicyclists like you fuck things up for the rest of us!" Remember, it's cars that screw things up, not other bicyclists, even hapless ones who do not have lights and ride on the wrong side of the street.
Which lights do I suggest? Get something a little nice that is fast and easy to install. The entire exchange should be very quick. The bicyclist stops and a minute later they are on their way with nice lighting. Don't buy something crappy. You can do better. When you give a set away consider buying another to replace it.
I chose these. Affordable and attractive, imo. Near instant install.
Why "Light Not Heat" - because I am sick of gutless jackholes who yell "I can't see you" at bicyclists. That's mindless heat. Let's light the night for bicyclists, not curse them out.