I used to sit in with a community band quite regularly some years back, and they had their wayof finishing up a performance with Ben E. King's Stand by me. Done that a few times, no problem.
So, I play the intro, just bass and drums, and as the rest of the orchestra comes in, the song goes up by one fourth. I had started on the D string instead of the G...
Last year, we were asked (read we had to, the town's administration had wanted us to do that) to play at a social evening of a sports event. The audience sucked, and me and the drummer had fun playing some particularly tasteless stuff.
The drummer was one of the locals pros, actually one of the finest you can find for many miles around. Now we played 'Cute', in which the drummer gets 2x 8 bars all for himself.
The second time, he stacked abouth three different samba rhythms on top of each other, and the sax players came back in about one and a half bars early. Trouble was, I could hear that they were playing, but not what they were playing, so I just played some very random walking bass until the end of the tune.
A few years back, I went to see Fairport Convention. Dave Pegg had just left Tull to rejoin FC.
One guitarist playes the intro to one song, and Dave almost falls off his chair, laughing. They tried it again, same result.
Several songs later, they make the third attempt, again, the guitarist blows it. They announce, 'the aforementioned song has left the building'.
And then there's the SAS Band. This is really as good as it gets for classic rock.
www.sasband.com
They usually finish up their show with 'with a little help from my friends', Joe Cocker version.
Chris Thompson starts by singing, 'would you believe if I sang out a song' or something like that, and then 'and I'll try not to **** up the words'. Needless to say, I was rolling on the floor. They simply started all over again.