Sometimes there's a great Cuban dance night in Ajax, Havana Nights. Other times, it's a lot of merengue, bachata, cumbia, and a little bit of salsa. In between sets, it's formula super-loud house music... a good time to get some fresh air !
But the good nights are great nights. It's hard to tell when to go, there's no detail on the website. If you talk to the people there, they vaguely tell you it's gonna be whatever you want it to be. ;-)
So, maybe one clue is when is Papiosco is signed to go out. In the next 2 months here're the dates: