Drop everything and read in this bibliophile's version of tag.
Setup: Decide the boundaries of the playing field and the location of the "library."
The player picked to be "It" chases the other players, who each carry a book. To save themselves from being tagged, players can stop running, open their book, and begin reading out loud. "It" can't tag them as long as they are reading audibly and standing still.
Tagged players are sent to the library -- a designated spot in the yard where they sit and read their books. To free them, other players have to run to the library and swap books with the tagged players. The last player to be tagged becomes the new It. The game ends when everyone is in the library -- or when everyone decides they'd actually rather sit outside and read.