In The Physics of Superheroes, Dr. Jim Kakalios asks if the comic book characters "could really do that?" to illustrate basic physics concepts. Here are some of Jim's public appearances discussing fragments of the book:
1) Death of Gwen Stacy (did Spiderman kill his girlfriend?)-
2) Electro & Magneto -
3) Superman's Blooper -
4) The Atom's Blooper -
Jim was an NPR Talk of the Nation guest last year and answered some questions from callers such as how fast the Flash needs to run to walk on water. A Slashdot post is also full of discussion and some additional links.