  Massive binary stars may constitute a substantial fraction of progenitors to
supernovae and gamma-ray bursts, and the distribution of their orbital
characteristics holds clues to the formation process of massive stars. As a
contribution to securing statistics on OB-type binaries, we report the
discovery and orbital parameters for five new systems as part of the Cygnus OB2
Radial Velocity Survey. Four of the new systems (MT070, MT174, MT267, and MT734
(a.k.a. VI Cygni #11) are single-lined spectroscopic binaries while one (MT103)
is a double-lined system (B1V+B2V). MT070 is noteworthy as the longest period
system yet measured in Cyg OB2, with P=6.2 yr. The other four systems have
periods ranging between 4 and 73 days. MT174 is noteworthy for having a
probable mass ratio q<0.1, making it a candidate progenitor to a low-mass X-ray
binary. These measurements bring the total number of massive binaries in Cyg
OB2 to 25, the most currently known in any single cluster or association.
