Mariachi's wearing sombreros
A Mexican bandito in a sombrero
A sombrero (Spanish for hat) was a wide, round-brimmed Mexican hat with a wide that could be turned up at the edges.
In 2366, after Q's powers were restored to him, he thanked the crew of the USS Enterprise-D with a small musical performance by a sombrero-wearing mariachi band. Q himself had a sombrero on his back. (TNG: "Deja Q")
In 2376, Harry Kim considered providing Tuvok's holoprogram of the Oracle of K'Tal with a sombrero, after Tom Paris had initially altered it to wear pajamas. (VOY: "Live Fast and Prosper")
In the 33rd century, Zora surprised Craft with "Taco Tuesday," hiding the synthesized tacos under a sombrero on the mess hall tray. (ST: "Calypso")