So how on earth can this be good? Sounds like you slap it together and throw it out there. Sounds like a reading you're paying Broadway prices to watch - or rather - merely listen to. So is it worth it?
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The answer to this question is a resounding YES provided the actors are ones you want to see - or rather hear. I suspect the secret to a production of this sort is to cast actors who generally embody the phrase "I could listen to them read the phone book".
The show itself is simply a recitation of various letters and thoughts exchanged between two friends over 40+ years who never quite caught up with each other as their lives slipped away in two vastly different directions all the while clinging to each other's letters for that single thread that bound together over time.
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This isn't much of a play. It's a sort-of-a-play. More like a long bedtime story read to you by two hopefully brilliant actors with irresistible voices. You'll either fall asleep happy in the theater (hopefully not) or leave the theater with a smile on your face after hearing such cherished actors tell you a story.