Superhero movies have been summer events ever since Superman: The Movie set the standard in 1978. (Okay, so it was released in December, but you know what I mean.) Audiences jam into the theater to watch the X-Men prance about, and Batman grunt, and Superman tote Richard Pryor around. But they’re generally not there because the movies are transcendent. They pay their money for the big reveal — that heady moment when Clark Kent pulls off the glasses, or Bruce Banner splits his pants. (I grew up on The Greatest American Hero and the Incredible Hulk television series, and nobody watched those for the story. We’re just counting the minutes until the hero appears. Even if he is clumsy and can’t stick the landing.)

The last couple of years have been interesting for superhero movies, with Marvel Studios taking a stronger approach to its own brand. A few early experiments — The X-Men, Daredevil, Blade — showed that audiences still turned out en masse for movies showcasing lesser-known characters. Several years of cooperative efforts between Marvel and other studios produced a series of interesting efforts, including the odd bomb (Ang Lee’s Hulk) and the just-as-rare critical success (Spider-man 2).

But with the enormous success of Iron Man two years ago, Marvel has set itself apart as a studio, carefully focusing on creating a cohesively-branded universe of superhero films. They’ve chosen experienced directors like Jon Favreau, and they’ve cast their movies with the sort of talent not often found in comic book movies, setting the gold standard with Robert Downey, Jr.’s performance in Iron Man and Edward Norton’s in The Incredible Hulk.

That was only the start, and what has followed is one of the most interesting stories coming out of Hollywood today. They’ve teased a larger universe of heroes in their existing movies, peppering them with characters like Nick Fury, and references to other heroes, like Captain America and Thor, each of whom will be carrying their own feature films in 2011. These characters, and more, will unite for The Avengers in 2012, a movie being helmed by Joss Whedon (RIP, Firefly). They’ve signed Samuel L. Jackson to an unprecedented deal — he’ll appear as Nick Fury in a whopping nine Marvel movies over the next several years.

This is perhaps the largest branding effort any studio has undertaken. Marvel has tasked Favreau with shepherding the brand, carrying the Iron Man aesthetic and tone into each of its future films by serving as a sort of brand consultant. Favreau had this to say in a recent interview:

“It’s going to be very interesting to see how the Marvel universe branches off … It’s going to be a big undertaking for Marvel to actually incorporate what happened in Iron Man, Iron Man 2, Thor, Captain America, The (Incredible) Hulk. All of that has to inform one unified vision for The Avengers.”

The movies so far have been a lot of fun. It will be interesting to watch Marvel attempt to pull this off over the next few years. Nobody wants another Spider-man 3, you know?