Absinthe, of sorts.
Bohemian crystal.
Art Nouveau posters/prints (Alphonse Mucha was Czech).
Garnet jewelry.
Communist paraphernalia/propaganda items (see Museum of Communism, just off Wenceslas Square, above a McDonald's for a truly ironic touch).
Beer, but somehow that never makes it home.

See Europe Forum. There's been a lot posted about Prague.