I like the Supers! Sourcebook. It contains a few optional rules, four new powers and a boatload of NPCs. My son grabbed it, read it and immediately wanted to make a new character that incorporated one of the new powers. And thus we started our Supers! campaign afresh.
He named his character Ken. Ken is an 18 year old who does not remember his past. He wakes up in a dumpster in an alley. A woman is being robbed by a band of thugs. Ken rushes to her aid and gets into a fight with the five guys. During the fight Ken discovers he has superpowers. He has super-strength and can mimic/become any substance he touches. (My son is a big fan of Ben Ten.) He turns to concrete and puts the thump to the bad guys, knocking three out and driving the other two off. He is making sure the woman is OK when the two that ran away come back with a big dude. Another fight ensues and Ken is victorious. In the meantime the woman called the police and they arrive just as Ken defeats the big guy. The police take the woman's story and take Ken and the bad guys to the station. The large, muscular but kindly Detective Kenyon talks to Ken in a room with a softly glowing green light. After being unable to determine Ken's identity the detective refers Ken to the home of a Mrs. Smith. Mrs. Smith takes in boys who are having problems, housing and feeding them until they get back on their feet. End of session one.
All the Rest 1
Mimic Substance 6