This is the organization I do my trackdays with:
click on "membership info" and then "TRY NESBA FOR FREE"
With their "INTRO" package, you get a 30min class room session and 2- 20 minute on track sessions in the moring to "try it out" and see how you like track riding. Minimal bike prep is required. They might have you tape over your lenses and lights and/or remove your mirrors but that's it. You need leather jacket and pants, boots, gloves and helmet. It costs nothing and they usually provide lunch too. Just register on their site, pick a date at the track you want to try and sign up for it. Then just show up at the track on that date at 7am.
There is a bunch of tracks we ride on:
Summit Point, WV - 2 tracks, 3rd being built
Pocono, PA - 2 different track set-ups
Beaverun, PA - track just opened this year, 2nd track planned
VIR, VA - 2 tracks