"Thow lookest as thou woldest fynde an hare,
For ever upon the ground I se thee stare.
Approche neer, and looke up murily;
Now war yow, sires, and lat this man have place.
He in the waast is shape as wel as I;
This were a popet in an arm tenbrace
For any womman smal, and fair of face.
He semeth elvyssh by his contenaunce,
For unto no wight dooth he daliaunce.
Sey now somwhat, syn oother folk han sayd,
Telle us a tale of myrthe, and that anon."
"Hooste," quod I, "ne beth nat yvele apayed,
For oother tale certes kan I noon
But of a ryme I lerned longe agoon."
"Ye, that is good," quod he, "now shul we heere
Som deyntee thyng, me thynketh by his cheere."
Chaucer the pilgrim is suggesting to his audience that he does not know many tales, and can only recall a single rhyme that he learned a long time ago.  This is rather humorous, since, knowing Chaucer the author, he clearly knows many tales and is a skilled story-teller.  It is also possible that by making his character out to be a bad story-teller, the opposite of his true self, that he is trying to remove his bias from the stories and create an omniscient narrator as much as he possibly can.
The Prologue of Sir Thopas in Middle English