Jeanne Tripplehorn was only supposed to be in season 8, but fans loved her so much that CBS decided to keep her for season 9.
The park mentioned at the beginning of the episode, Bonsall Park, is a real park in Glendale, AZ.
Reid talks about Pheidippides after whose legendary run the Marathon is named.
Pheidippides true story is actually far more impressive than the popular version.
His journey was actually 153 miles, not 26.2 miles. (26.2 miles was the distance from the starting point in the grounds of Windsor Castle in London to the finish line in front of the Royal Box in the stadium, so the Royal Family could witness the beginning and the end of the race.)
Pheidippides ran from Marathon to Sparta to request reinforcements for the upcoming battle, only to be told that they were in the middle of a religious festival and were prohibited from fighting for several more days. So Pheidippides ran back with the Spartan's reply. A total of 153 miles, cross country, in 3 days.
Little else is known about Pheidippides. Some stories say he stayed in Marathon and participated in the battle, between trips to deliver messages, but no contemporary accounts mention his death.