Underpants Bandits

The Underpants Bandits is a book series by Mik Davies, which focuses on two boys named Bryce and Brody who go back in time to steal underwear from famous people so they can put them in a museum. There are 26 known books in the series. They were banned in Greg's school because of the rude humor. Some of the books include:

Lincoln's Longjohn's

Something with Van Gogh (unknown title)

Trivia

 * This may be a spoof of Captain Underpants, a book series by Dav Pilkey, due to the authors' similar names and rude humor, and "Underpants" in the title.
 * This may also be a spoof of Time Bandits, a 1981 British fantasy film. Both books include characters going back in time and stealing things.