Fish and coins
One of the highlights in the monastery is the huge kitchen.
There, a tank is always freshened by running water, diverted from the river.
In my last visit I noticed that merging two traditions may lead to silly things: someone decided to put fishes in the tank and some other people keep throwing coins to the water.
Both things don't go well together - copper is poison to fishes, so the result will be easy to guess!
Carnival by the Monastery
It's not an old tradition, but the Carnival parade by the Monastery has been strengthening, and, though too much commercial for my taste, became an extra attraction subject.
Now they changed - Carnival is in a tent or out of Alcobaça, mainly in... Turquel (guess why!), but the monastery is still there (maybe hidden by a tent...).