World's Oldest Marathoner

Buster Martin of the UK may become the world's oldest marathoner at 101 years old.  He's already the UK's oldest employee as he still works a full-time job!  He plans to attempt the London 2008 Marathon.  He recently completed the Roding Valley half marathon in Essex on Sunday, March 2, 2008 in five hours 13 minutes.
Yahoo! News article
Buster's Wikipedia page