  This is my contribution to the Festschrift honoring Stephen Hawking on his
60th birthday. Twenty-five years ago, Gibbons and Hawking laid out the
semi-classical properties of de Sitter space. After a summary of their main
results, I discuss some further quantum aspects that have since been
understood. The largest de Sitter black hole displays an intriguing pattern of
instabilities, which can render the boundary structure arbitrarily complicated.
I review entropy bounds specific to de Sitter space and outline a few of the
strategies and problems in the search for a full quantum theory of the
spacetime.
