"No Ordinary Visitors" - George gets pulled over. There's a small lead up at this might be some sort of dark humor moment as George is a black man driving slowly very late at night in a nice neighborhood that's had a string of home invasions lately. Instead? George pulls out his ADA badge and gives the police officer a verbal lashing about how many amendments, rulings, procedures, and whats the guy is breaking just for pulling him over as he did and finishes off with another before getting back into his car.
"No Ordinary Accident" - JJ and Stephanie use their powers to save a man's life surgically, something that no doctor seemed to be able to do.
Based on JJ's explanation, no one else could do it since the pipe was keeping him from bleeding out completely. Only Stephanie with her super-speed could pull the pipe out and stitch the artery close before that could happen.
Jim stops a freight train. With his bare hands.
JJ showing off his powers in detention by making it snow. Also a good and reasonable way to reveal his powers compared to practically ever other show that might do this. Instead of simply saying "I'm super smart", people asking a few questions, and then simply taking it for fact, he simply gives a The World Is Just Awesome speech and does something amazing.
Jim and Stephanie fighting against the serial arsonist with fire powers.