In the US and Mexico , the US practical joke group Improv Everywhere has created an ` international celebration of silliness ' by asking commuters to board the New York and Mexico City subways without trousers on a specific day .
In the U.S. and Mexico , the practical joke group Improv Everywhere has created an `` international celebration of silliness '' by asking people to get on the New York and Mexico City subways without trousers on a specific day .