Say that you do not already have a pending teaching job out there and have not applied yet for graduate school, but you see teaching as a great career path to take. If you are particularly civic-minded, a volunteering type, highly ambitious and desiring to make a difference, there are alternative routes into education. One could apply with Teach For America (TFA), which is affiliated with AmeriCorps. You will undergo a summer training program, and then be embedded in an urban or rural school district, often in need of more teachers. You will meet with corps members and be observed often, but will be gaining teaching experience on the job. The TFA program requires expectation of at least a two-year commitment, and the group will work with local universities so you may work toward a master's degree in education or teaching, both to go from provisional to full certification, but also to complete an education degree for a reduced cost. It is possible to complete the master's during your two-year commitment time frame, making the years of college required for becoming a teacher more manageable and interesting.
There are similar programs across the country, including teaching fellowships. These programs do not shorten the length of time to complete a teaching degree but allow for it to be an immersion experience, which benefits more than just yourself.
Additional specific alternative routes are highlighted in a Department of Education report, "Innovations in Education: Alternative Routes to Teacher Certification," including pathways in Florida, Texas, Georgia, New York, California, and Kansas.