Your question is wide open. There are too many "good enjoyable plays" to keep a short or even medium length list.
But you have to start somewhere. Find a list of the three big prizes for drama: the Pulitzer Prize, the Tony Award and the NY Dramna Critics Circle Award. often the winners over lap.
Take the list to the library, pick one and start reading. Plays read for pleasure don't take long--60-120 minutes.
You can also then take a look at a list of long running plays, but keep in mind that commercial success does not always equal quality.
Or read by author:
O'Neill
Miller
Williams
Shaffer
for instance.
This is just contemporary work. There is the whole pre-1920 pantheon too!
Enjoy.
"If my life weren't funny, it would just be true. And that would be unacceptable."
--Carrie Fisher
