fantastic

(noun): A fanciful or whimsical person.
(adjective): Existing in or constructed from fantasy; of or relating to fantasy; fanciful.
(adjective): Not believable; implausible; seemingly only possible in fantasy.
(adjective): Resembling fantasies in irregularity, caprice, or eccentricity; irregular; grotesque.
(adjective): Wonderful; marvelous; excellent; extraordinarily good or great (used especially as an intensifier).

He told fantastic stories of dragons and goblins.
She entered the lab and stood gaping for a good ten minutes at the fantastic machinery at work all around her.
"I had a simply fantastic vacation, and I can't wait to tell you all about it!"