This is a very simple launch/display platform for the LEGO Ideas NASA Apollo Saturn V (set 21309).
I mostly built it so that I could see the glow from the LEDs I put in the engines when the model is displayed vertically, but I think in general it finishes off the model nicely. The real thing never sat directly on the engines, so it adds a bit more realism in my mind.
It's a very simple model, so a lot of opportunity to use different pieces or decorate it differently.
In the beginning of the video you can see what the Saturn V looks like sitting on it.