We all get accustomed to the things we see around us all the time. I grew up in Alaska, so it's easy for me to sometimes forget how many people have never seen the Northern Lights (aurora borealis).
But I will say that no matter how many times you see the aurora, it's always an incredible sight. You never get cynical about it, and after a particularly spectacular display, the next day everyone's talking about it. Even the crusty old sourdough dudes with their bushy white beards and decades of cynicism will stop and watch the aurora in silent awe.
I also forget how many people have an inaccurate mental image of what the Northern Lights are like. Almost all the footage you see of the aurora has been sped up a few hundred times to show the movement. In reality, the lights move so slowly that you can only barely perceive the rippling effect. I have had to deliver the unfortunate truth to many people who have only seen the sped-up footage on television!
The aurora happen when charged particles from the solar wind interact with the Earth's magnetic field. When they collide with the magnetic field they light up, giving off a different color depending on the kind of particle.
Your best chance to see the aurora is in winter, thanks to the long nights and the darker sky. The University of Fairbanks recommends looking for the aurora between December and March. The later at night, the better the viewing. New moon and sliver moon nights are the best, to reduce the amount of moonlight interfering with the display.
If you want to DIY your viewing experience, plan a trip to a northern city (like Fairbanks). Bundle up in as many layers as you can don, pack a thermos of coffee, and find a spot to watch the sky as far from the city lights as possible.
Many companies offer aurora tours in winter. But it seems that Chena Hot Springs is really bringing their "A Game" to the party. They have a special coach that will drive you up to a nearby ridge where you can watch from a heated yurt (with coffee and hot cocoa provided). They also have an "aurorium," which is a special heated cabin with extra-large bay windows so that you can view the aurora from indoors. Coupled with an aurora wake-up service that will phone your room when the light show starts.