Laser pointers are a lot of fun, provided you don't point it in an eye or try to hit a overflying airplane.  But hitting the International Space Station is 100% OK, provided you communicate your intentions to an astronaut.

No one had successfully hit the ISS with a laser pointer.  The San Antonio Astronomical Association decided to attempt the task.

Yes, a lot of math was involved.  It also took some time to coordinate the effort with Don Pettit, an astronaut on the ISS.  Email communication is not instantaneous, there are two to three email packets sent per day.  They also had to wait for the ISS to cross over San night.

Finally early on Sunday, mission accomplished!