The first DLC of Cities Skylines. Adds leisure and tourism commercial district based specializations. Leisure commercial areas are more active at night hours.
Adds also a few leisure related parks, some changes as to how criminals are processed, taxis and some transport related assets, and a few unique buildings.
The price of the DLC is very steep to what it adds to the base game, especially those that cannot be obtained via Workshop.
Note that the game's name may be misleading to some - day and night cycles are included in the base game, and the DLC is NOT required for that functionality.
Overall, I like it and still recommend it, despite the high price, but strongly suggest waiting for a sale, that at least happens fairly enough. 6/10 at full price.