Spider-Man: Turn Off the Dark, currently running on Broadway, is still in previews and will be until (they claim) March 15. How many other plays ran a long time under the mantle of "previews" before opening? Not many. This article will tell you about one that Jackie Mason attempted as both star and co-author back in 1969. It ran 97 previews before it finally opened and critics gave it the finger. Thanks to Bruce Reznick for calling this to my attention.