In case you want to bet on this, consider buying sherritt.com . This is probably the company that would benefit most from an end of the embargo, as it owns some mining and oil rights on Cuba.

Disclaimer: I myself bought this stock somewhat below 4 CAD. Now its at 2.67 CAD. :(

EDIT: Honestly, why the downvotes? I for one would be very happy if people shared more of their thoughts about how one could trade particular potential events. But maybe hackernews is the wrong community for that...