Way too many to list, and half probably forgotten across the decades anyway lol, but richardinwales's mention of Elkie Brooks instantly reminded me of being in Brighton on business overnight in '77/8, and after tea at the hotel I went off for a wander around for a while. The hotel was on the Front on a corner with one of the roads leading down to it, and I thought I'd walk along, take a look round The Lanes, wander up in to the Town after and look it over, probably find a decent-enough place to stop for a drink or two at some point, and then head back with a stroll along the beach on the way.
I got as far as somewhere around where the Odeon cinema is today - maye even it was that then too but also as a gig venue - with an awning that had "Elkie Brooks" on it and with its doors open. I liked EB, the sign said 7:30 start and it was just gone 7:15 by my watch so on a total impulse born from an accident which arose out of a coincidence, I walked in and they had a number of good stalls seats open on the Plan, from which I chose the one that was right up front (of course!) and enjoyed a super and unexpected couple of hours!
Which has in fact just brought back something similar but 3,500 or-so miles away: My career was shared between here and the US for most of it's 45-yr span, and for a good part of that I would spend anything from 2-4 months a year across there in visits that might be for just a couple of days or might be for a few weeks. I chose Washimgton DC for my main Eastern base as I was associated wth a US firm there who were happy for me to use their office etc as my own when across.
A couple of trips prior to one DC-visit I had been going through the music channels on the in-flight entertainment, and my ear was instantly caught at one point by something from a band I had never heard of, called Blues Traveller who have since gone on to greater success in the US and also over here too in their niche sector as I am sure many here now will know. Before returning home I made sure to find a couple of their albums to bring back with me.
So, on this later visit to DC I dropped my stuff off at a room I would often stay in at the Arts Club, which being a member of the NY Arts Club made possible on a reciprocal basis, which was great because it was like having a private Apartment!
A little later when I had changed and freshened after the long flight I went across to where there was a little convenience store to pick a few things up for the room, also to check out the menu on the restaurant next to it where I would frequently eat .. and which was already calling to me anyway because whilst only late afternoon there I was at mid-evening or later body-clock time and needed a proper meal!
And that was when I noticed a handwritten poster on a board by the convenience store, saying Blues Traveller had a gig that evening in the Gym at George Washinton University .. which was literally steps away and right around the corner! So I walked up to the corner out of curiousity, and could then see the end of a short queue that had started to form ... so, forgetting the restaurant I went and joined the queue - sorry, the line - with my bag of room snacks, lol.
Over the hour or so before it opened to let people in, I had a great time just chatting with people around me who quickly noticed an English accent in a conversation and would join-in, amazed to find anyone from overseas who had even heard of this little-but-rising new kinda-wacky-folksy-bluesy band!
I had to confess that they were new to me too since hearing them only once and for the first time a few weeks back on a flight, and that it was entirely a fluke that I had just flown-in and discovered they were gigging right across the street with just enough time for me to settle and change and join the line!
And at that point I was "Wow dude, fantastic!"-ed close to death by their fans
In fact I must have had similar conversations with a few different groups between then and being inside and around where I was seated, at times re-repeated by someone calling to a friend to come over with their friends too and meet me and hear what brought me 3,500 miles to their Gym
...
And after the (superb!) gig .. not a monster crowd in a major venue, note, but in the fantastic atmosphere of I'd say 500-550 tops in a school gym with bleacher seating and marked out with a basketball court (!) I joined a couple of the groups for a drink or three nearby, and was then split from there to go on with a few others to somewhere else for a couple more ... all awesomely friendly and inviting, just me and couple of hundred new best-friends!
So, an entirely out-of-nowhere great night that happened only because of a string of things occurring that led to that trip starting in the UK on that day with that flight, and to me ending up at that store just then after getting in, just to pick up room-snacks and then seeing that notice.
Just makes you wonder sometimes!