I went Saturday. It was very cool. A few notes, in no particular order:
Remember that the subject matter is cool, but it's still a museum. If you don't like museums (looking at things through glass, then trying to read the little descriptions below), you might not like this. They have quite a few audio and video and audio/visual stops, though, which are pretty neat. If you have any eye troubles whatsoever, take a pair of binoculars. Some of the descriptions are real hard to read.
The basement is a circle, with rooms in the middle. It starts with the early influences (Mississippi Delta) and ends with more recent stuff (I can't remember the exact exhibit). The circle is kind of in chronological order, but not completely (the Jimi Hendrix exhibit is one of the last ones you come to, and there's obviously been a lot of rock-n-roll after him).
What struck me most is that the bulk of the artifacts surround the years 1964 to 1974. I guess it makes sense, since a ton of stuff happened during those ten years (Beatles and Stones, psychedelic, peace and love, the arrival of the full concert (with pyrotechnics and stuff), punk, folk music, start-up of Rolling Stone magazine), but I'd never thought of it that way, until I noticed that (I'm guessing) half of the basement deals with those ten years alone.
Anyway, if you're in the Cleveland area, it's well worth the $20 and the trip. If you're with a friend, buy a membership. It cost me $50, and it came with two free passes (value: $40), plus a t-shirt, lunch tote bag, decal, a one-year subscription to Rolling Stone magazine, a subscription to Liner Notes (the official Hall publication), and a 10% discount in the gift shop. That's a lot of decadence for just $10.
I don't have any pictures. I have a picture of the kids and me, standing near Lake Erie, but the place was pretty crowded and nearly all of the artifacts are in rooms that don't allow pictures.