NEW YORK (AP) -- Author-vloggers Hank and John Green often end their popular "Crash Course" videos with a donation appeal to keep the YouTube show "free for everyone forever.

In the wake of the USAID closure, philanthropies are trying to fill some of the gap.

As the official celebrations of the 250th anniversary of the signing of the Declaration of Independence culminate on July 4, a well-financed, privately funded initiative will kick off to try to connect hundreds of millions of Americans with efforts to solve local problems.