Deborah Baker first introduced me to this series of books in 1982, and I read the first nine in the 1980s. The books are set in a pun-infested world in which people have individual magic powers that they must discover. The first time travel that I remember was in the 1979 Castle Roogna where characters could step into a tapestry that took them to the past.
It was embroidered with scenes from the ancient past of Castle Roogna and its environs, eight hundred years ago.

Variants

(1)
  1. Xanth by Piers Anthony (July 1979).
    2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . written by Piers Anthony