The PhilipGlass.com performance calendar is a good resource for performances but by and large most of the ballet performances (hundreds of performances) are not listed there. This is for a couple reasons - first is that frequently ballet companies perform to recordings and not live music. Secondly when the performances are worked out with the publishers, they get the right to a number of performances, 10 for example, and don't necessarily communicate back as to when those performances will take place - it might be 10 performances spread over three years.
This is to say that things sneak up on me when not widely publicized or found through the normal channels.
This week, the Pacific Northwest Ballet is performing/performed "In the Upper Room," the Cincinnati Ballet, building on the recent Glass activity in Cincy which included his Creative Directorship at the Cincinnati Symphony and this summer's Cincy Opera's performance of his opera Galileo, performed a work with Glass music, and I see the Boston Ballet will perform the Chuck Close ballet "C. to C." next season.
In other news the Library of Congress has taken 25 recordings into its archives. This round of inductees includes the early recording of Einstein on the Beach.