Fox doesn't seem to be able to let go of Kiefer Sutherland's superhero Jack Bauer, so on the 5th of May he returns with the mini-series 24: Live Another Day (a clear reference to Die Another Day). I absolutely hated the original 24 series, seriously, I can't think of any other show what annoyed me that much, but I'm sure there are many people who can't wait to see it.
Penny Dreadful, which airs on the 11th of May on Showtime seems a bit more interesting. Basically, they take a bunch characters from various spooky novels (e.g. Dorian Gray and Dr. Frankenstein) and put them to Victorian London. The show is created by John Logan, whose writing credits include Skyfall and The Aviator, and features Bond girl Eva Green, who plays one of the main characters.
On the 22nd of May a new action drama Gang Related premieres on Fox. The series is created by Chris Morgan (Fast and Furious) and it is about L.A. Police Department's special Gang Task Force and its war on gangs. Latinos will hate it, I'm afraid.
Then we have three new series from NBC. On the 27th of May they release The Night Shift about the night shift ER doctors from San Antonio Medical Center.
Two days later NBC introduce a sitcom Undateable by Adam Sztykiel, which is based on the book Undateable: 311 Things Guys Do That Guarantee They Won't Be Dating Or Having Sex. It's about a bunch of guys and their unfortunate lack of dating skills. The first look promo is here.