Marvel Heroes is receiving an update today to promote the new movie which comes out next Friday.
All the Avengers roster of the cinematic universe (Black Widow, Captain America, Hawkeye, Hulk, Iron Man, and Thor) are available in the starter hero lineup. Also, these heroes have a 50% exp boost.
The patrol zones will also have Ultron bots to fight.
If you ever thought about trying Marvel Heroes, looks like this week is a good time to pick an Avenger and get a jump on leveling.