August 10, 1966 was a Wednesday, and it gave Wes Wilson one of his odder Fillmore commissions: a poster, BG-22, for Sam the Sham and the Pharaohs — the Tex-Mex novelty-rock outfit behind "Wooly Bully" and "Li'l Red Riding Hood" — at the Fillmore Auditorium. The support act, per the poster's own phrasing preserved by SFMOMA and FAMSF, was the Sit-Ins; the FAMSF record credits Wilson as designer and the West Coast Lithograph Company as printer. It was a single night, not a run, and it is a small reminder that Graham's 1966 Fillmore was still a working dance hall that booked chart acts, not yet the temple of the psychedelic underground it is remembered as. The bill — a Top-40 band with a domino-masked frontman, on a Wes Wilson poster, at the Fillmore — is exactly the kind of collision the scene threw up in its transitional first full year.

A year later, August 10, 1967 was a Thursday, and it opened the Avalon run that Moby Grape crossed town to headline after leaving the Fillmore: Moby Grape, Canned Heat, and Vanilla Fudge, August 10 through 13, under Victor Moscoso's FD-75, the poster known as "Three Bares." The Museum of Fine Arts Boston and FAMSF both preserve the Moscoso sheet. This is a genuinely strong bill — Moby Grape at its brief commercial peak, Canned Heat months from Monterey-fueled fame, and Vanilla Fudge riding its slowed-down "You Keep Me Hangin' On" — and it ran directly opposite the back half of the Electric Flag run at the Fillmore, giving San Francisco two heavyweight blues-rock bills on competing stages that weekend. One detail that circulates about this run: Corry Arnold notes that Mad River substituted for Moby Grape at the last second on one night — probably Saturday, August 12 — apparently because Skip Spence was incapacitated; Arnold himself is unsure of the particulars ("no one seems to know what it is"). We record that as the single-source, hedged story it is, and specifically not the garbled "Mad River sat in on Moby Grape's amps, August 11" version that floats around elsewhere.

The other 1967 thread on August 10 is the Fillmore itself, mid-run on BG-77, and it is the crux of the Moby Grape scheduling puzzle. By August 10 Moby Grape was opening its own Avalon stand (FD-75) — while Corry Arnold's Moby Grape chronology still books the band at the Fillmore that same night, an August 10 two-venue overlap he flags as unresolved. What the BG-77 poster does show is the Steve Miller Blues Band added to the Electric Flag bill for the run's back half, the likeliest way the Fillmore absorbed Moby Grape's move. So August 10 is exactly where the puzzle sits: the same band advertised at two ballrooms on one Thursday, and no vetted source that cleanly resolves which stage it actually played.

In 1969, August 10 was a Sunday and the closing night of a David Singer poster that is a small catalogue of misfortune. BG-185 advertised the whole Fillmore West week, August 5 through 10, and its back half — August 8 through 10 — was Junior Walker and the All Stars, Lee Michaels, and Tony Joe White. The front half, August 5 through 7, had been sold as Fleetwood Mac and SRC, but Fleetwood Mac did not play; the bill that actually took the stage was Butterfield / It's a Beautiful Day / SRC (which the chronicle heroes on August 6). Jerrybase records a deeper wrinkle: the run had originally been booked as a Grateful Dead / Fleetwood Mac double headline, and both fell through — and when the Dead dropped out, David Singer removed their name from the artwork at the last moment, leaving, by that account, a blank spot on the finished poster. So BG-185 carries two defects at once: an advertised headliner (Fleetwood Mac) who didn't appear, and a ghost where the Grateful Dead had been erased. Junior Walker's Motown soul closing the week is the part of BG-185 that went off as printed.

But the hero of August 10 is 1966: Sam the Sham at the Fillmore on a Wes Wilson poster — a Top-40 novelty act in the middle of the room where the counterculture's defining posters were being drawn, on a single Wednesday night that catches the Fillmore before it fully became the Fillmore.