JAMBOREELighter - RHDHASlang p 248 attributes n. [orig. unkn,; earlier (1864) as a term in euchre and later a "boisterous celebration. Next reference is 1868.
RHDAE - has no historical origin but suggests
[appar. b. JABBER and SHIVAREE, with modification of from JAM CROWD - Crowds jam the doors.
Sincerely,
Gargoyle