anecdote

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A short account of an interesting or humorous incident.
• noun Secret or hitherto undivulged particulars of history or biography.

from The Century Dictionary.

• noun plural Secret history; facts relating to secret or private affairs, as of governments or of individuals: often used (commonly in the form anecdota) as the title of works treating of such matters.
• noun A short narrative of a particular or detached incident or occurrence of an interesting nature; a biographical incident; a single passage of private life.

from the GNU version of the Collaborative International Dictionary of English.

• noun Unpublished narratives.
• noun A particular or detached incident or fact of an interesting nature; a biographical incident or fragment; a single passage of private life.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A short account of an incident, often humorous.
• noun An account which supports an argument, but which is not supported by scientific or statistical analysis.
• noun A previously untold secret account of an incident.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun short account of an incident (especially a biographical one)