This one’s a twofer.
You get to do something super cool while impressing your girlfriend in a romantic setting.
You’ll need to find a field that is frequented by fireflies and accessible by car.
Some night, when the fireflies are out, drive your girlfriend to said field and park with the car’s headlights pointed at the field of fireflies. Make sure you turn the headlights off before the car is facing the fireflies.
Next, turn your headlights on and off quickly one time. The fireflies will react by blinking on and off themselves, en mass.
Pretty cool, huh?
Don’t say I never gave you nothin’.