The goggles w/ binaural beats create some weird sort of state where I don't feel any connection to my environment. After only a couple minutes my body turns to total mush and my brain comes alive with phosphene visuals. By about 15 minutes in, my stomach usually gurgles a bit, not unlike the indigestion that often accompanies psychedelic trips.
Interestingly enough, these machines are marketed as brainwave entrainment, but the literature on that says the visual component doesn't really have much impact. Yet auditory entrainment on its own doesn't seem to do much for me either, or at least, not convincing enough beyond placebo.
There is an app for the iPhone called Lumenate that uses the LED flash and it seems to work, though it's not as strong for me as the multi-LED goggles I used to use. Still, it's a great gateway for those who are curious.