  We report the discovery of widespread maser emission in non-metastable
inversion transitions of NH$_3$ toward various parts of the Sagittarius B2
molecular cloud/star forming region complex: We detect masers in the $J,K = $
(6,3), (7,4), (8,5), (9,6), and (10,7) transitions toward Sgr B2(M) and Sgr
B2(N), an NH$_3$ (6,3) maser in Sgr B2(NS), and NH$_3$ (7,4), (9,6), and (10,7)
masers in Sgr B2(S). With the high angular resolution data of the Karl G.
Jansky Very Large Array (JVLA) in A-configuration we identify 18 maser spots.
Nine maser spots arise from Sgr B2(N), one from Sgr B2(NS), five from Sgr
B2(M), and three in Sgr B2(S). Compared to our Effelsberg single dish data, the
JVLA data indicate no missing flux. The detected maser spots are not resolved
by our JVLA observations. Lower limits to the brightness temperature are
$>$3000~K and reach up to several 10$^5$~K, manifesting the lines' maser
nature. In view of the masers' velocity differences with respect to adjacent
hot molecular cores and/or UCH{\scriptsize II} regions, it is argued that all
the measured ammonia maser lines may be associated with shocks caused either by
outflows or by the expansion of UCH{\scriptsize II} regions. Overall, Sgr B2 is
unique in that it allows us to measure many NH$_3$ masers simultaneously, which
may be essential to elucidate their so far poorly understood origin and
excitation.
