A few years ago, at my *very* local "town day" 5 miler--a race hotly contested among "local champions" (but no others)--was smoked, SMOKED I tell you, by a mystery woman (yes, a woman!).
Cassandra Henkiel, a ranked triathlete, was in town for a wedding and decided to just show up for the local race, winning with a 5:29 pace, finishing about 30 seconds ahead of the #2 runner... and looking MIGHTY FINE in the process. Lotta bruised (male) egos that day!
Also, at this year's Run Your Hangover Off race on Jan 1 (another *very* local affair), Casey Moulton (a newly qualified olympic-trial hopeful with a 2:20 'thon) slummed his way to a win with something like a 5:01 pace...