  The instanton/sphaleron processes involve gauge fields with changing topology
through a nonzero variation of the Chern-Simons number $\delta N_{CS}=\pm 1$.
In QCD this leads to the production of $2N_f \delta N_{CS}$ units of axial
charge, and in the electroweak theory to the production of 12 fermions, with
$\Delta B=\delta L=3$ units of baryon and lepton number, a key mechanism in
baryogenesis. While this is all known for a long time, and is one of the
pillars of the nonperturbative theory of the QCD vacuum, to see these phenomena
directly in colliders remains an unfulfilled promise. Motivated by the recent
CERN workshop on the topic, we review the field. We also put forward our own
suggestions to utilize double-diffractive (or Pomeron-Pomeron) collisions to
this goal, which maximizes the entrance factor and minimizes the backgrounds.
  We consider separately clusters of small ($M=3-10\, {\rm GeV}$), medium
($10-30\, {\rm GeV}$) and high $M\sim 100 \, {\rm GeV}$ invariant masses. Among
the proposed signals are specific flavor combination of channels, originating
from well-defined 6-, 8- and 10-quark-antiquark operators, as well as
correlation of quark chiralities to be potentially detected via $\Lambda$
hyperon decays.
