My 1950's comment was a joke. The decrepit Beach Boys concert two years ago was pretty bad.
Cheap Trick formed in 1973, active since 1974. There biggest hits were "I Want You to Want Me" (1977; live 1979 version was more popular), Dream Police (1979). You can count the 80's if you like that God awful song "The Flame" (1988).
Source: http://www.cheaptrick.com/about-the-band
Source: http://en.wikipedia.org/wiki/Cheap_Trick
Kool & the Gang formed in 1964. Most of their hits were in the 70' & early 80's: Jungle Boogie (1973), Hollywood Swinging (1974), Ladies Night (1979), Too Hot (1979), Celebration (1980), Get Down on It (1981). Later they released Joanna (1983), Fresh (1984) and Cherish (1985), but those songs don't have the party feeling as Jungle Boogie, Ladies Night, Celebration, etc.
Source: http://koolandthegang.com/history/
Source: http://en.wikipedia.org/wiki/Kool_%2...ng_discography
Bonus Source: I am old, have gray hair and used to buy albums.