jamboree \JAM-buh-ree\, noun:
1. A carousal; any noisy merrymaking.
2. A large gathering, as of a political party or the teams of a sporting league, often including a program of speeches and entertainment.
3. A large gathering of members of the Boy Scouts or Girl Scouts, usually nationwide or international in scope
Several thoughtful riflemen had foregone the shooting jamboree to place themselves as cover guards for the MG.
-- James Jones , The thin red line
Well, the great jamboree was over at last, not only the jamboree of the two Armistice Days (and really, we could have celebrated a dozen), but of the past several years.
-- Charles Jackson , The sunnier side: Arcadian tales
Jamboree is an American invention, an apparent blend of jabber and shivaree.