(1)
If I were Fidel, I would INVITE tens of thousands of Haitian refugees to come to Cuba where they would be "welcomed with open arms"...as long as they are 'encouraged' to spout off some anti-American slogans when they land in Cuba. Hopefully to EMBARRASS America's government over its lack of interest in Haiti's problems of late.
In a few weeks these guys would head back to Haiti where there is at least SOMETHING to eat.

(2)
I would then as leader of Cuba indoctrinate those 'grateful' Haitians in virulent anti-Americanisms, perhaps training them on AK-47's, RPG's, and explosives to become....
dare I say "troublemakers' in the hemisphere?
Castro has done that many times before. Unfortunately, most of his colleagues in the Revolution business have been marched in front of Castro's own firing squads. This leaves a deficiency in trained manpower.

(3)
I would also make deals with either Communist China or North Korea to ship supplies of Scud missiles and Silkworm ASM's, taking advantage of the Pentagon's excessive focus on Iraq. Since Bush would be forced to repeat JFK's actions against Cuba [a revived October Crisis?], I would as FIDEL try something 'ominous' at the perimeter of Gitmo, perhaps having the Cuban army use the perimeter of Guantanamo Bay for 'artillery practice'.
That would GUARANTEE an invasion from the USA. Not a re-run of the "Bay of Pigs" fiasco, but a massive invasion by air and sea. Blitzkrieg, in other words. Sort of like what happened to Iraq. There are PLENTY of Cuban exiles over here who would create a new, ultra-pro-USA government in a few weeks. They would hunt down Castro's remaining supporters gladly and for nothing.

(4)
Naturally, Bush and Rumsfeld would threaten to use B-52's, F-18's, and B-2 bombers against 'my' Cuba army in response. I as FIDEL would be forced to 'claim' [lie through my teeth] that my beloved 'Cuban Army of Liberation' has a right to carry out 'artillery practice' on sovereign Cuban soil!...But I FIDEL will express "regrets" over a few artillery shells and rockets landing on the American Base in "error".
By this time, Fidel Castro would not have any teeth left. He would h ave to lie through his gums, if he and them left, that is.

(5)
Then to really TWEEK the American's nose, I would install huge loudspeakers near the base perimeter to BLARE out anti-American propaganda onto Guantanamo Bay, loud enough for the Taliban/Al Qaeda detainees to hear, hoping to generate a RIOT among them, hopefully EMBARRASSING Bush and forcing him to evacuate those detainees ELSEWHERE.
By this time Castro would either be: dead, in exile in North Korea, or in jail.

In other words, Castro stays in power because the USA has not been sufficiently pissed off to remove him. As soon as Castro antagonizes the USA sufficiently, he will be ashes. Remember Manuel Noriega. Where is he today?