Most Bill Harley material is good stuff, so even a random free track from him would have a good chance of getting mentioned here.
But "Down in the Backpack"? One of Harley's most well-known songs? Almost guaranteed to get a grin out of your 7-year-old? (And probably you, too?)
Just go here, where "Down in the Backpack," the title track from Harley's 2001 album, is free 'til the end of the month.