  We present the discovery in Kepler's $K2$ mission observations and our
follow-up radial velocity observations from Keck/HIRES for four eclipsing
binary (EB) star systems in the young benchmark Pleiades cluster. Based on our
modeling results, we announce two new low mass ($M_{tot} < 0.6 M_\odot$) EBs
among Pleiades members (HCG 76 and MHO 9) and we report on two previously known
Pleiades binaries that are also found to be EB systems (HII 2407 and HD 23642).
We measured the masses of the binary HCG 76 to $\lesssim$2.5% precision, and
the radii to $\lesssim$4.5% precision, which together with the precise
effective temperatures yield an independent Pleiades distance of 132$\pm$5 pc.
We discuss another EB towards the Pleiades that is a possible but unlikely
Pleiades cluster member (AK II 465). The two new confirmed Pleiades systems
extend the mass range of Pleiades EB components to 0.2-2 $M_\odot$. Our initial
measurements of the fundamental stellar parameters for the Pleiades EBs are
discussed in the context of the current stellar models and the nominal cluster
isochrone, finding good agreement with the stellar models of Baraffe et al.
(2015) at the nominal Pleiades age of 120 Myr.
  Finally, in the Hyades, we report a new low mass eclipsing system (vA 50)
that was concurrently discovered and studied by Mann et al. (2016). We confirm
that the eclipse is likely caused by a Neptune-sized transiting planet, and
with the additional radial velocity constraints presented here we improve the
constraint on the maximum mass of the planet to be $\lesssim$1.2
$M_\mathrm{Jup}$.
