Great thread and wonderful stories!
I'll relate three that all happened almost without fail every gig during a number of tours I did with a Vegas style show band I played with.
The entertainer I worked for was an excellent vocal impersonator whom had the gift of gab and comical wit and timing unparalleled. He had everyone in our audiences eating out of his hand and spellbound with the wonders of our show every time we played.
1.) During the course of our shows, in which we played mostly 30 second to 1 minute snippets of the songs by famous artists he was impersonating, interspersed with song related historical verbalisms and jokes, he would hand signal us unobtrusively (and seemingly magically out of thin air to the audience) to stop playing instantaneously, and then immediately launching into the next bit. Without fail, after each show as we mingled with the audience I would hear or be commented to by a wonderously baffled audience member how we managed to stop playing instantly ... "How do you guys do it?" I heard time and time again. After the first few times I'd say, "Well, erm, ahhh, we just lift our hands off our instruments", which would leave the questioner with the same tilt-headed, eyebrow-scrunched, baffled look. In time, and after continually seeing the bewilderment on their faces after my answer, I just decided to tell them that we had learned and practiced a special and secret musical technique perfected by master musicians from ancient times past. Upon hearing that they would inevitably get a suitably impressed look of understanding accompanied by a breathy "Ahhhhhhh ... Wow!!!"
2.) One of the tunes we played was Orange Blossom Special in which the entertainer would show off his masterful skills on the fiddle. In reality, he knew next to nothing about playing this instrument other than making himself look highly skilled through his fake actions, whilst I played the fiddle licks on a string synth (Crumar Performer I believe?) trying to look invisible. He would prepare for the song by over resining his bow, and plucking more than a few bow hairs loose from one end, so that as he was whirling around on stage resin dust would be flying around in clouds and bow hairs would be doing the same. We had the thing tuned so that he could actually play each string as we modulated chords and had it just barely loud enough in the PA so that the real fiddle sound would blend in with my synth. Again, without fail, folks would always tell him that he was "one of the best fiddle players they'd ever seen!!!"
3.) During one leg of a tour we lost and had to hire replacement girl backup singers (we had a large band), but we were short on time before the next show and were in a very rural area. We quickly threw together some auditions but only one of the girls could sing well. So, we hired her (she was rather homely looking) and two hotties that couldn't sing their way naked out of a shower to save their lives. For the show, we dressed them all three up in their gowns, put the homely but angelic voiced one in between the two cuties, with a live mic for Miss homely and dead mics for the two hotties. And yet again, after every show we played with them guys would come up to the two lip-syncing dead mic'd hotties and tell them that they had the greatest voices they'd ever heard, completely ignoring Miss homely.