What's a jam band?
I like all kinds of music: blues, rock, psychedelic, R&B, jazz and ocassionally even folk/bluegrass and their offshoots. And I especially like long, well-developed performances that I can get lost in -- the kind of music that musicians love playing as they engage a melody and soar side by side like the Blue Angels in tight formation and then diverge into solo musical loops and barrel rolls, eventually converging back at the melody where they started. This kind of musical aerobatics is the domain of the jam band.
In introducing its comprehensive and always-growing list of jam bands, Wikipedia summarizes: "Jam band performances often feature extended musical improvisation ('jams') over rhythmic grooves and chord patterns, and long sets of music that cross genre boundaries."
Elsewhere, Wikipedia traces jam band origins: "The jam-band musical style spawned from the psychedelic rock movement of the 1960s. The Grateful Dead and The Allman Brothers Band became notable for their live improvisational jams and regular touring schedules, which continued into the 1990s." Wikipedia also identifies the "stylistic origins" of jam bands to include: jazz, folk, country, psychedelic rock, progressive rock, jazz fusion, blues, rock, and Southern rock. In fact, many jam band tracks (songs) seem to slide effortlessly among several of these musical genres within the same piece.
(Rather not read my wise & wonderful background info? Then scroll down & start listening.)