The International Space Station is one of the brightest objects in the night sky when it can be seen. If you know when and where to look, you can even see it from your house. It looks more or less like a really fast-moving plane—so fast, actually, that it's only visible from a specific place for a few minutes at a time.
But now you don't have to do a ton of mathematical equations or rely solely on luck to spot the ISS at night. NASA just launched a program called Spot the Station that sends you an alert whenever the ISS is going to be passing over your house. All you have to do is sign up, and they'll send you a text or email a few hours before so you know when to look.
Depending on its orbit, NASA says you may get alerts "anywhere from once or twice a week to once or twice a month," and they'll only notify you of "good" sightings. The alerts tell you the time, duration, maximum height, and the locations where it will enter and exit your field of vision (you can see an example here).
The best sightings are on clear nights, and you can see the station with the naked eye. Here are some examples of what a good sighting looks like:
To sign up for alerts, you just need to enter your city and a valid email address or mobile phone number. If you don't want to sign up, you can also check NASA's Satellite Sightings Information page and it will just give you a list instead.