A slang reference to the sport of basketball. Probably stems from the fact that professional basketball players are predominately of African origin and basketball is an exceedingly prominent element of young black culture in America.
See also: nigger ball
Steve: Hey, Tim! I've got two free tickets to go watch the Lakers on tuesday. You in?
A hardo is a person who tries extremely hard at everything. Most times a hardo will try very hard at things that do not require excessive effort. For example, sports practices, gym class, etc.
Wow did you see Jack at practice today? What a hardo!