Participants can go to http://events.stanford.edu/ to search what's happening at Stanford, so you could possibly attend performances at Bing, Memorial or Dinkelspiel Auditoriums, for example. Here's a site with lots of information https://visit.stanford.edu/plan/guides/visit.html. You can find a map of the Stanford campus here.

For the afternoon-off Thursday you may want to consider one of these options:

• Cantor Museum and Anderson Collection are both open till 8 PM [closed Tue]
  Tours also on weekends for those staying after Amplitudes
• Rodin Sculpture Garden near Cantor Museum
• Burghers of Calais near Main Quad
• New Guinea Sculpture Garden
• Memorial Church
• Hoover Tower
• Stanford Dish hiking trail
• Nice walk from Stanford campus down Palm Drive to downtown Palo Alto for dinner

Reminder: Parking is free on campus after 4pm Mon-Fri and all weekend