Onnen päivät was released in the year 1974。Onnen päivät is also called as "Happy Days", New Family in Town, Jours heureux, Happy Days Again, Happy Days, Gänget och jag, Días felices。

Richie Cunningham and his friend Potsie face life at Jefferson High in Milwaukee Wisconsin in the 1950s. Originally fifth-billed Fonzie moved up steadily, finally into first billing in 1980, as the thumbs-up, "Heyyy!" biker increased his own and show's popularity. Lots of changes over time as kids come and go, new series spin off, Richie and pals go to college then the army. Even marriage.

Onnen päivät actors and actresses include Anson Williams, Cindy Williams, Crystal Bernard, Don Most, Erin Moran, Heather O'Rourke, Henry Winkler, Kevin Rodney Sullivan, Linda Purl, Marion Ross, Pat Morita, Scott Baio, Ted McGinley, Tom Bosley。