According to my 11-year-old son Ian, "There's rock music, there's metal, there's classical, and then there's Kayak."
(I couldn't find any samples of this song on the internet, so I made one myself.)
One article I read called this "crossover-prog," which is as close as one could get to categorizing this wonderful, slightly wacky music. If you haven't heard Kayak's 1975 album Royal Bed Bouncer, track it down. Tuneful and joyful; it never gets old. If this appeals to you, check out their other three early albums (Kayak, See See The Sun, The Last Encore). It's timeless music that fits any mood.
I'm also happy to say that after breaking up in the 80's, they reformed in the 2000's and are still recording and performing. Check them out: Kayak homepage
(Thanks again Steve, for giving me this album out of the blue, back when we were teens. I've still got it!)