Some years ago, a professor described nonsensical dreams as a "brain flush." He said it was the brain's way of disgorging all sorts of unconnected baggage that had been stored up there.
In college, we used to joke about doing a "brain dump" right after taking an exam for which we had crammed for hours.
Had rather a brain flush last night that included tram rides in a town that has no trams; a tallish and heavyish woman on the tram, in town for a conference, asking me what there was to do, and me telling her about the available shopping centers (and me feeling bad for such a stereotype response, except in that town shopping was the only thing to do!); getting into a van which I had rented before leaving town (plane, train, bus? don't know how I departed or to where), and discovering there was a helicopter on the roof of my van, attempting to take off in a very dangerous confined area -- I warned them they'd better not try to take off because I have friends at the FAA!
Most of the time I don't remember much at all about my dreams. This one was so off the wall, I got up and took notes.