Tournaments come in different sizes, durations, and type.
There are currently three sizes:
Small Tournaments: Warmups or Fight Pits, for example.
Medium Tournaments: Weekend Tournaments, for example.
Large Tournaments: Special Events and Big Monthly Tournaments, for example.
Each tournament will have an specified duration and prize which you can check on the Lobby.
Also, each tournament awards a different amount of XP to the Top 10 or 20, depending on the tournament, and to the remainder of active players.
Tournaments can be of two types:
Regular: all rates and times are as described on the wiki.
Turbo: rates are multiplied 4.5 times and times are divided 4.5 times.
Turbo+: same as Turbo but plus some buildings already leveled up (which buildings get extra levels from the start will be announced at the start of each tournament).
Duration of tournaments will be announced beforehand and those can range from 3hs up to 48hs.