I think the definitions and models (the four path model specifically) from the pragmatic dharma crowd are the most interesting by far. Mostly because they can be tested. It's (Theravada) Buddhism stripped of a lot of the religious dogma.
They describe awakening as an actual, irreversible natural process that can be triggered by concentrating your awareness onto bare experience for a long enough time. Doing this intensively enough will bring about a "discontinuity" / cessation of space-time experience called a "fruition" (nirvana). Coming out of that discontinuity goes with a blissful "what was that?" feeling and some level of understanding of "ultimate reality", meaning a permanent perspective shift (instead of "I am seeing" and "I am hearing": in seeing there is merely the seen, in hearing the heard, etc...).
They describe awakening as an actual, irreversible natural process that can be triggered by concentrating your awareness onto bare experience for a long enough time. Doing this intensively enough will bring about a "discontinuity" / cessation of space-time experience called a "fruition" (nirvana). Coming out of that discontinuity goes with a blissful "what was that?" feeling and some level of understanding of "ultimate reality", meaning a permanent perspective shift (instead of "I am seeing" and "I am hearing": in seeing there is merely the seen, in hearing the heard, etc...).