I'm currently at Supercomputing '22:

  https://sc22.supercomputing.org/

As the name suggests, it's a very large conference on supercomputing
and HPC in general, this year held in Dallas.  It is (far) larger than
any conference I have previously attended; likely because of the
significant industry interest in the topic.  The expo hall itself is
very large, and most booths sell solutions to problems I didn't even
know exist.  I am particularly amazed at just how many vendors sell
various novel (or not so novel) cooling systems.

HPC is on the periphery of my work, so while the more
programming-related material is interesting, a lot of what is
happening here is well outside my wheelhouse.  I'm surprised at how
relatively crude many of the still-popular programming models are.