“Thor”: Not quite a marvel from a box office point of view. (Mark Fellman/MARK FELLMAN)

Thor” got the summer off to its weakest start in five years, landing at the top of the box office, but with only $66 million in revenue. Does this suggest that the upcoming season will be a lackluster one from a money-making perspective, or that audiences don’t care for Norse heroes with hammer fixations?

Let’s analyze that and cover more lessons learned from the weekend box office results — including some that may involve Mel Gibson — after the jump.

“Thor”is a respectable but not phenomenal superhero: Let’s start with the positive when it comes to “Thor.” It definitely outperformed its competition, earning an estimated $30 million-plus more than second-place finisher “Fast Five.” Given its headstart overseas, “Thor” already has earned $242 million worldwide, which is hardly shabby.

But just looking at the domestic box office side of things, “Thor’s” $66 million North American take is less than the total amassed by last week’s No. 1 movie, “Fast Five,” which earned an impressive $86.1 million in its opening weekend. It’s also much less than than the debut revenues for other recent summer-movie-season ribbon-cutters, including both “Iron Man” movies and “X-Men: Origins: Wolverine.” You have to go back to the first weekend in May of 2006, when “Mission: Impossible III” debuted with only $47.7 million following Tom Cruise’s couch-jumping era, to find a softer summer-season start.

Of course, despite Hollywood’s insistence that the first weekend in May is officially popcorn-crunching time, moviegoers may not be in summer movie mode yet. And even if they are, “Thor” — a non-sequel with both a mythology and a leading man (Chris Hemsworth) that not everyone is familiar with — may not have possessed the elements needed to lure the masses to the multiplex.

The appeal of hot cars wears off quickly: In the shadow of “Thor’s” dominance, “Fast Five” business dropped substantially, with the movie earning just $32.5 million. Nonetheless, that was enough to push the Vin Diesel flick’s total gross to $139.8 million, making it the highest earner of 2011 so far.

If you open a pair of wedding comedies during the same weekend, you might wind up with a rom-com tie: Both “Jumping the Broom” and “Something Borrowed” made roughly $13 million a piece, with “Broom” (13.7 million) in third place ahead of “Borrowed” ($13.1 million) by the slimmest of projected margins. But even if they wind up swapping places when final box office figures are released Monday, “Jumping the Broom” is the real winner here. The African-American ensemble comedy made more than the Ginnifer Goodwin/Kate Hudson effort, on one-fifth the budget and without as much marketing to back it up.

Jodie Foster and a beaver puppet weren’t enough for a Mel Gibson comeback: At least not yet. In limited release on 22 screens, “The Beaver” made a paltry $104,000, despite largely positive notices from critics. Not a good sign for Gibson and Foster, although the true test will come May 20, when the drama rolls out in more theaters.

Here are your top five movies of the May 6-8 weekend:

1. “Thor” — $66 million

2. “Fast Five” — $32.5 million

3. “Jumping the Broom” — $13.7 million

4. “Something Borrowed” — $13.1 million

5. “Rio” — $8.2 million

And here’s the weekly poll that allows you to predict next weekend’s winner; can “Priest” or “Bridesmaids” overthrow “Thor”?