Beyoncé performed at the 2013 Super Bowl haltime show and flashed the pyramid sign. The Roc Sign or Roc-A-Fella sign represents her husband Jay Z’s record label. See Jay Z and the Roc Sign.

Super Bowl 2013 haltime show

Beyonce and Jay Z

Beyonce explaining the Roc-a-Fella sign (also)

Super Bowl XLVII haltime show general info on Wiki