What's a word for "a thoroughly enjoyable experience"?

What's a word for "a thoroughly enjoyable experience"? Something like the opposite of a "trial"?

A pleasure?

The condition or sensation induced by the experience or anticipation of what is felt to be good or desirable; a feeling of happy satisfaction or enjoyment; delight, gratification. Opposed to pain.

A treat?

Something highly enjoyable; a great pleasure, delight, or gratification.

A delight?

Anything in which one takes delight, or which affords delight; an object of delight; a source of great pleasure or joy.

(All from the OED.)

"Slang" terms that I've come across for "pleasurable" are "lark," and "lulu."'

That was a lark. or That was a lulu.

If you mean something that gives pleasure: Delight

a high degree of gratification : joy; also : extreme satisfaction

something that gives great pleasure

If you're talking about the state of mind: Bliss

complete happiness

There are also joy (which can be used in both contexts), pleasure, and felicity.