A Rickroll, or rickrolling, is a popular online prank originating on Youtube. Being Rickrolled, occurs when a person sends a link that holds a youtube URL to a version of Rick Astley's music video "Never Gonna Give You Up" in place of what the recipient had expected.
Recently, The New York Mets had an online ballot for a song to be played during the season. Multiple Online Communities, originally Fark.com, lobbied users to write in Astley's Video. The vote for the ballot reached a much larger audience than expected and with the inclusion of a write in option, and Rick Astely's song was chosen, and subsiquently played on the Met's Shea Stadium Scoreboard, effectivly rickrolling the entire crowd of baseball fans.