A noisy, drunken game of dominoes is being played at the Committee for the Defense of the Revolution (CDR) on Havana's San Lorenzo street, the pieces slapped down on the bare wooden table to the accompaniment of colorful, if amicable, abuse.
"We may have problems, my friend," says one player, as a bottle of white rum does the rounds at the Saturday night game. "But we have Fidel. He has the answers."
The fading posters on the wall feature quotes from "the commander-in-chief," President Fidel Castro, urging Cubans to "keep up their guard." The room smells slightly of stale urine but the reception is one of typical Cuban warmth.
"If someone steals your wallet on the street here, I will run after them myself and get it back," promises Lazaro Gonzalez who, though 74 years old, means what he says.
He has no doubts whatsoever that, 44 years after Castro and his bearded rebels swept into Havana to oust the corrupt regime of Fulgencio Batista, the revolution is alive and kicking. "This is the most marvellous revolution in the world," he says.
If you want to find diehard adherents of Castro's version of state socialism, you can do no better than visit any of the thousands of CDRs, each pledged "to carry out the revolution in every neighborhood."
The San Lazaro CDR organizes nightly neighborhood patrols to keep eight city blocks clear of crime. It is an objective that, in a safe city already patrolled by numerous police, is reached with few problems.
But here, as almost anywhere you turn in Cuba, contradictions quickly emerge. For the CDR has a nastier reputation as a Cuban Big Brother, snooping on the neighbors and watching out for "counter-revolutionaries," wherever they may hide.
When Ivan, a student, refused to sign last July's state-organised referendum declaring Cuban socialism "irrevocable," his sister signed his name for him. "She wanted one of the television sets the CDR was giving away," he explained.
On a Havana street corner a billboard carries the boast "200 million street children in the world, and not one of them Cuban."
Cuban children are just as likely to reach the age of five as their counterparts in the US At current rates they will live to 76, one year less than in the US.
The few children on Havana's streets during the day are invariably dressed in neat school clothes. Their teachers claim they are serious students who flourish without the distractions of the consumer society. Literacy rates reach 96 percent. Again, however, the contradictions soon appear. Some of the girls will go on to find a career in jineterismo -- looking for European sugar-daddy tourists, or simply selling their bodies to sex punters for US dollars.
David Hickey, an Irish surgeon and professor at Havana University, says Cuba does amazing things with limited health resources. "They are short of virtually everything, but I am amazed at the integrity and commitment of the Cuban doctors," he says.
When Castro wanted to show the film director Oliver Stone the splendours of the Cuban revolution while he was filming his recent documentary, Comandante, they travelled to Havana's Latin American School of Medical Sciences. Castro was mobbed by some of the 3,400 student doctors from Latin America, and even a few from the US, studying for free at the Cuban government's expense.
However, the head of surgery at a Havana hospital, Mr Hickey complains, may earn less in a month than a hotel waitress gets in tips in a single day. Little surprise, then, that some doctors work nights as taxi drivers or that others have abandoned the profession entirely.