OpenStreetMap
These are the Markham Fair grounds. I missed out some of the grass, and the track, but this is pretty much what you get. It doesn’t look much like tourism=theme_park, does it? But that’s how it’s currently tagged: Way: Markham Fairgrounds (43934707)
Strangely enough, it and many others like it in Ontario are tagged as theme parks. Now they might have a midway for a week or so during summer or fall fairs, but the rest of the time, they look like this.
The previously proposed amenity=show_grounds would be better for most of these. The ones that have permanent installations, like Canada’s Wonderland, should stay as theme parks, so a little local knowledge is required.
Discussion
Comment from BushmanK on 5 November 2016 at 21:05
Since fairgrounds are a subset of commercial use land, it would be completely correct to tag it with
landuse=commercialif someone wants to stick to approved tags. This way to describe it is very broad, but fairgrounds could be used for an extremely wide range of events.Comment from scruss on 5 November 2016 at 21:38
Some are commercial, others are municipally-owned.
landuse=commercialis too broad.Comment from BushmanK on 5 November 2016 at 22:11
As it often happens in OSM, certain terms have slightly different meaning than in real life. Same applies to commercial land use. In OSM, it does not indicate ownership or form of property, it does indicate a purpose of this land. In the case of fairgrounds, majority of activities taking place there are usually commercial.
Comment from Warin61 on 5 November 2016 at 22:18
In country areas of Australia showgrounds get used for sports (cricket, football), camping as well as annual shows - not all at the same time. I do map the camping and sports parts as those are well documented in OSM. But annual shows (sometimes there are more than one - usually of different focus) are not something OSM handles well. To me landuse=recreation covers shows, camping and sports so I tend to use that.
Comment from Warin61 on 6 November 2016 at 00:46
Arr .. found my comment for showground under recreation_ground talk … “A ‘showground’ can be tagged landuse=recreation_ground with recreation_ground=showground”
Cannot say I stick by what I said, but there you are.