How about this for a "hotel race"* venue?
These are the tracks for the 24 Hours of Madrid event, one of three 24-hours races organized this year by Slot Racing Cup. The event begins tomorrow, June 5, and runs through Sunday, June 7. The facility is, as best I can tell, an indoor soccer fieldhouse.
Kinda makes our "big" races here in the US look pretty anemic, doesn't it? The organizers are also providing a sleeping and showering facility for the racers when they are not on the track.
Here's a pic of an earlier Slot Racing Cup event that seems to be in the same facility.
And I think this is the 2015 Slot Racing Cup Valencia venue, which was located in a large shopping mall as best I can tell.
* "Hotel race" = US slot racing jargon for an event held on track(s) temporarily erected in a non-raceway venue.