Step1
Learn The Basic Criteria for a School's Being a HBCU.
There are about 114 schools that are considered HBCUs. The Higher Education Act of 1965 defines an HBCU as “any historically black college or university that was established prior to 1964, whose principal mission was, and is, the education of black Americans, and that is accredited by a nationally recognized accrediting agency or association …”
Many HBCUs are private, but no small amount are public.
Step2
Learn the Geography of HBCUs.
The vast majority of HBCU's are located south of the Mason-Dixon Line, though in my research I was a little surprised to find that there's even one in my state, Michigan, called Lewis College of Business. None appears to be west of Texas, and one HBCU is actually in the Virgin Islands, named aptly enough, University of the Virgin Islands.
Please see under "Resources" below, the List of HBCUs by state.
Step3
Learn Famous Alumni.
The famous alumni of HBCUs are far too numerous to mention here, but a sampling: Dr. Martin Luther King Jr., Oprah Winfrey, Ed Bradley, Walter Payton, Jerry Rice, Langston Hughes, Ralph Ellison, Alice Walker, Toni Morrison, Branford Marsalis, Thurgood Marshall . . . Please see the link below under Resources - Indices of Famous Alumni.
Step4
Learn A Little About HBCU Sports (and Pep/Marching Bands).
As hinted at in the introduction, the main way in which I came to know of HBCU as such was through NCAA sports. In NCAA Division I, there are two main conferences that consist in HBCUs, the Mid-Eastern Athletic Conference (MEAC), and the Southwestern Athletic Conference (SWAC). Arguably the most famous school in the MEAC is Howard University, in Washington, D.C., and in the SWAC is Grambling State University in Louisiana. In NCAA Division II, the Southern Intercollegiate Athletic Conference (SIAC) is also representative of HBCUs.
It's interesting to watch basketball games from these conferences, and even more interesting to watch the football games (due to the marching bands). As mentioned before, both CSTV* (please see Warnings below) and ESPNU carry HBCU sports, consisting mostly (though not exclusively) in the MEAC and SWAC. One reason why it's fun to watch MEAC and SWAC sports is because it's a nice break from "big" schools, but also the bands and pagentry are spectacular! HBCU bands put on the best shows, and sometimes when watching HBCU sports it almost feels like you went to a concert and a game broke out! There is much dancing, and I think the bands often play (at least for football) while the game is going on, not just during major breaks!
For more on the bands and on MEAC and SWAC schools, please see Resources below.