The Osmonds will reunite this summer to celebrate a half century in show business. Alan (58), Wayne (55), Merrill (54), Jay (52), Donny (49), Marie (47) and Jimmy (44) will perform August 13 & 14 in Las Vegas at The Orleans Hotel Showroom. Though some of the siblings have not even reached 50 years yet, the four older brothers began performing together as The Osmond Brothers in 1957. They were regulars on the TV series The Travels of Jaimie McPheeters (1963 to 64), starring Kurt Russell, as well as on The Andy Williams Show from 1962 to 1971, with Donny joining the act in 1963. Tickets will range from $75 to $125. The show will be taped to air on PBS next March.