  Cosmic ray events above 10^19 eV have posed a fundamental problem for more
than thirty years. Recent measurements indicate that these events do not show
the features predicted by the GZK bound. The events may, in addition, display
angular correlations with point sources. If these observations are confirmed
for point sources further than 50 - 100 Mpc, then strong interactions for the
neutrino are indicated. Recent work on extra spatial dimensions provides a
context for massive spin-2 exchanges capable of generating cross sections in
the 1 - 100 mb range, as indicated by data. Applications of extra-dimension
physics are controversial, and we comment on several contentious issues.
