18 channel internet radio station, you only have to go as far as Milwaukee's Summerfest to find the answer.
Along with contemporary artists like Girl Talk, Jason Mraz, Guster, Maroon 5, Ben Harper, Fuel, The Black Keys, Katy Perry, Britney Spears, and Meat Puppets, the "World's Largest Music Festival" also showcases a ton of boomer friendly acts.
AARP, an organization of which I am now a member, is populated with people who came of age during the summer of love. Their ranks are filled with Deadheads, Beatlemaniacs, and Disco divas. As such the channels are not all Sinatra and Doris Day (although you will find them there).
AARP knows as well as any organization that people do not adopt the attitudes of the demographic they're moving into. They bring their attitudes and behaviors with them. Just because I'm an AARP member, doesn't mean I'm all of a sudden going to move to Boca, buy a Cadillac DTS and start eating dinner at 4 in the afternoon.
If you want to stay relevant, pay attention to the people who are moving into your brand family and be ready to evolve.