Has there ever been an occurrence where a very well known artist or band - The Rolling Stones, for example – played a small venue (e.g. a bar that seats 100) unannounced? Or perhaps under a pseudonym?
This Google search mentions Arcade Fire, U2, Nirvana (a new incarnation with Joan Jett), Green Day, Metallica, and more. I didn’t study each of the cases but looks like some would qualify.
The Beatles rooftop concert should qualify as well.
The Rolling Stones have done it a number of times. Here’s a recent example.
The first Wings tour consisted entirely of unannounced appearances at various university campuses.
Why yes. In fact the Rolling Stones themselves did it at least once.
Edit -Ninja’d
I’m pretty sure Blue Oyster Cult (not bothering with the umlauts) played gigs as their previous name, Soft White Underbelly, at small clubs in the early 80’s.
Not a band, but Robin Williams showed up and did a set at an open mike night I went to.
And Hank Aaron showed up and talked at a baseball event I was at, where the scheduled speakers were Tom Glavine and Mark McLemore.
Back in the 80s when they were big Blue Oyster Cult would often play small club gigs in the New York area. It became an open secret that they would play under the name Soft White Underbelly which I believe was their original name.
Edit: Dammit!
That is normal. Big comics do short sets in clubs to work on new material or keep their timing sharp. The Comedy Cellar in NYC is famous for this. Nightly you can still see Louis CK, Chris Rock, Jim Norton and others unannounced. In fact Louis uses the Cellar’s front door in the opening credits of his TV show.
And in 1989, just before they started the Steel Wheels tour. They had been rehearsing for that tour at a girls’ school in Connecticut that had recently closed, and they played a surprise performance on a Saturday night at Toad’s Place in New Haven. (The owner of the club was called the previous day to make the arrangements.)
R.E.M. did it many times over the years.
The Stones were also going to play an unannounced show in Providence, but cancelled when a local TV station announced it.
http://news.google.com/newspapers?nid=1314&dat=19810920&id=SWsjAAAAIBAJ&sjid=ae4DAAAAIBAJ&pg=4506,2143505
And 35 years later, Paul McCartney played a surprise in-store gig at Amoeba Records.
Rush did it at least once as part of some radio station’s promotion. The station broadcast that a ‘name’ band would play a small club and it was a mystery but get your tickets now.
Neil Young and Crazyhorse used to gig at bars all over Northern California back in the 70s while they were rehearsing for a tour.
Yes, in the early 90s they did some absolutely incredible shows in small clubs under the name Bingo Hand Job. (I used to have some bootlegs of them). Billy Bragg and Natalie Merchant guested at some of them.
Not quite the same but there’s a well known youtube video where Jewel dons a disguise and performs at a Karaoke club.
It did, but having been present at one of those gigs I can tell you it was not a small venue by the standards of the time. It was the same hall that was usually used for concerts, and at other times I saw many other bands and artistes that were big at the time play normal “announced” concerts there: Led Zeppelin; Deep Purple; The Rolling Stones; Pink Floyd; The Kinks; Jethro Tull; Emerson, Lake and Palmer; Leonard Cohen; to name just a few of those who are still fairly famous. The Wings gig was odd not only in being unannounced, but in taking place on a Wednesday afternoon rather than a Friday or Saturday evening. (I only found out about it because I saw people lining up when I was on my way back home after a class, and because I saw I guy I knew on the Entertainments Committee, whom I was able to ask what was up.) Nevertheless, the hall was about as full as it got for a normal weekend gig. IIRC, I think it held about 2,000 people. That was a large venue back in '72.
Yes- one of the pseudonyms they used to use was “Fat, Drunk and Stupid.”
(Name that movie!)
Decades ago, after playing a big concert in Austin, U2 dropped by Antones, a local blues club, and did some songs there.
Now, it’s more common for famous comedians to do unannounced appearances at small clubs, to try out new material. My brother saw Jerry Seinfeld (who was already a big TV star at the time) doing that at a small club in Queens- I forget the name of the club, but the place USED to be a bowling alley, and I think the club name reflected that.
I almost got to see The Sex Pistols, in 1977, when there was a huge buzz about them in Britain, and when they did a brief tour under an assumed name (or, maybe a series of assumed names) of small clubs around the UK. There was a tiny club I used to go to quite regularly (I doubt whether it could have held as many as 100 people at full capacity), and one time I and the friend I was with noticed a very small notice by the door, written by hand in black ballpoint, announcing a gig by The Sex Pistols the next week. Needless to say, we turned up the next week, but The Pistols did not. 
The story was that they had cancelled because of the notice that we saw. The band had made a very strict stipulation that the gig should be totally unannounced, and pulled out when they discovered that even this very discreet announcement had been made. I think they intended to play under the name The Hamsters. However, I believe that at this time they did play unannounced at a number of other small clubs around the country, probably under other assumed names.
Mind you, at this time The Sex Pistols may never yet have played a large venue, but their reputation was such, at this time, that they cold certainly have easily filled one.
Now, to combine comedy AND the Soft White Underbelly. Years ago, I was on Who Wants to Be a Millionaire (I never answered any questions and never won any money), where I met Rudy Reber, a former standup comci who lost a huge pile because his phone a friend, political comedian Will Durst. gave him the wrong answer.
Anyway, Rudy told some great stories about his days as a struggling comic, and he told us that a comedian friend of his once got a gig at a small club as opener for some band called the Soft Whte Underbelly. The friend had no idea that this was an alias for a (then) very popular hard rock band! He barely escaped with his life, as a crowd of drunken metalheads isn’t very patient with non-musical warmup acts!
The Beach Boys have done a few. Most notably in Waikiki for their 25th anniversary.