Last week four Massachusetts men were arrested, accused of stealing the “buried treasure” they claimed to have discovered while doing a roofing job. Some have speculated that the quartet allegedly stole the wad of antique cash to gain wealth, fame or both. But the cynic in me came up with another rationale: Perhaps it was all a brilliantly executed marketing stunt related to this week’s DVD release of “National Treasure.”

Surely Buena Vista Home Entertainment had nothing to do with that bizarre turn of events. But the New England news story did break at a coincidentally fortuitous time. Not that “National Treasure” needs the boost. As one of the highest-grossing movies of 2004, sales of this single-disc release will likely be brisk. Before you rush out and buy it, consider the following. The film — about a treasure hunter (Nicolas Cage) eager to get his hands on a historically significant map on the back of the Declaration of Independence — is occasionally fun but mostly formulaic. After watching it once, most viewers probably won’t feel the need to view it again.

With a very creative approach to its bonus material, however, the DVD almost compensates for the movie’s shortcomings. In keeping with the treasure hunting theme, each of the extras reveals a pair of letters. After watching the four initial features, viewers can enter those letters to spell a secret word (don’t worry, even 6-year-old Sherlocks can figure it out), which then yields a new menu screen with an additional set of bonus features. It’s a clever approach and one that compels the audience to check out all the supplemental material, or at least fast-forward through it to get to the next clue.

Unfortunately, few of the features — which include a dull making-of documentary, two deleted scenes, an alternate ending, a featurette about real-life treasure hunters and interactive puzzles — are worthwhile enough to merit the effort. But somehow I doubt that will stop owners of the DVD from trying to solve “National Treasure’s” mysteries. After all, as those four guys from Massachusetts might agree, it’s hard to resist the prospect of a buried treasure, even if finding it ultimately leads to a dead end.