What do Uno and his father do the first Saturday of every month?

The
answer to this question can be found in the chapter titled "Spaghetti with Meatballs."
The chapter begins with Uno's father, Senior, giving his son life wisdom through a leopard
.

The text then breaks in order to inform readers about Senior and Uno. We
are told that as long as Uno can remember, his biological father, Senior, drives down to
National City from Oxnard on the first Saturday of every month to spend time with Uno.

As readers get to know Senior, we realize that he has an entirely different life up in
Oxnard. He is no longer involved with street violence. He has a new wife and a new baby boy;
however, he feels obligated to maintain contact with Uno and be as much of a father figure as he
can. Senior will go so far as to offer Uno a chance to join him up in Oxnard, and large parts of
the book are about Uno trying to earn enough money to make it happen.