I am surprised this isn't featured on the LetsRun main page report from Stanford. Certainly the performance of the meet.
Haile Gebrselassie 2:03:59 Marathon at age 35, 27:06 10k at age 35, and 2:08:17 Marathon at age 38!
Paul Tergat 2:10:22 Marathon at age 40!
Bernard Lagat 12:53.60 5k at age 37!
When put into perspective, the 28:57 isn't particularly impressive.