My boys love these books. If your kids liked either the "Fly Guy" books or the "Bad Kitty" books, what are some other ones they loved? Mamma could use a break from these charactors - just something else ... anything else.
I don't know if I can help in the way you like-- my son is six and loves those books, but he also adores Captain Underpants, Frankenstein and we are devouring an adaptation of Beowulf right now. Scatological humor and horror.
Oh, how about the Teacher from the Black Lagoon books by Mike Thaler? He also does a Class from the Black Lagoon chapter book series. Kiddo loves those!
The Pigeon series is funny and easy to read. (Don't Let the Pigeon Drive the Bus, Pigeon Finds a Hot Dog, etc) Biscuit books are good for beginning readers. They have short, repetitive, simple sentences that build confidence. Pete the Cat books are nice for young readers too but with longer pages than Biscuit. Henry & Mudge books are wonderful and the characters are endearing. They're for readers transitioning to longer books and my first grade son loves them. When we first started the series, I would alternate reading a page and then my son would read a page. Now he's reading them on his own. :) Not sure the ages of your boys but the Weird School series and Magic Treehouse series have been a hit with my second grader who's a more advanced reader.
You could try the Mercy Watson series. Mercy Watson is a pig that lives with Mr. and Mrs. Watson and you get to meet all kinds of interesting characters in their neighborhood.
You also might try:
Splat the Cat series
Diary of a Wimpy Kid series
Babymouse series
For your younger son I recommend Mo Willems. The Pigeon books are very, very funny.
My Weird School is loved by my daughter that liked Bad Kitty.
Splat the Cat
Pete the Cat
Little Critter
Froggy
Characters my son loves. He also likes Bad Kitty.
