Original 1st printing (OP-2 in the Eric King guide, the lighter/"money" green version) 13&7/8 x 19&7/8" concert poster for the Grateful Dead appearing with the Oxford Circle at the Avalon Ballroom in San Francisco, CA on 11/4-5/1966.
Art by Alton Kelley and Stanley Mouse, image is # 33 in the Family Dog/Avalon series.
Medium-thick flat vellum stock poster is in good (B) condition; multiple/pin/tack holes in each of the four corners, in the ticket outlet area and on the "ir" of "Circle", an approximately 3 x 5" area of discoloration in the lower right corner and about 1" along the bottom margin (the rest of the poster is evenly toned, but there had been another piece (or pieces) tacked over part of the corner and bottom margin), plus a bit of light handling wear, a couple of corner bumps, a few small drip stains on the reverse and a couple of tiny surface marks, otherwise fine.
The fascinating aspect of this example (to me, at least...) is the positioning of the lighter/non-toned area; from the looks of it, this example really looks like it was originally displayed in public in 1966, presumably on a bulletin board with a number of other pieces. There has always been some debate on which version of the FD 33 is the "original" (light versus dark green), but given that this one has all of the markings of public display, it gives a fairly strong argument towards this version being the first one that was actually distributed to advertise the shows.