A towel, is about the most massively useful thing an interstellar hitchhiker can have.

Towel Day is celebrated every May 25th.

In 2009 Towel Day fell on Memorial Day. I was lucky enough to have a US Flag towel. I traveled from 42nd & 12th to Broadway, up Broadway to Central Park, walked through most of the lower park area, over to the Apple Store on Fifth, took the train to Coney Island, walked all over the place looking for fellow Towel Travelers and found none, other than that strange guy trying to hitch a ride under a Martian Spaceship.

In 2010, same strange traveler gets onto a Downtown 6 Train and is joined by two Towel Travelers in the same car! Go figure. Finally we see our hero with his same trusty Towel in one of his favorite bars waiting for his Pan Galactic Gargle Blaster.