Wear nice shoes
Being a former theater, the high ceilings and large dance floor create an expansively grand, but not cavernous, atmosphere that is a refreshing change from other LA spots that take the idea of being "cozy" with the fellow revelers they pack in to the place a little too far. The architecture and decor designed to resemble Mayan stone carvings make the place historic but avoids feeling kitsch. The music is energetic and the Salsa dancing was fun to watch for those of us not quite up to more than quick try at the elaborate hoofing on display by the skilled regular patrons.
Cover is a bit steep at $18, but considering its a club with live music at times, there is more of an entertainment quality then you would find at a normal bar. There are also two other dance floors in the basement and on the second floor playing more a more general dance music mix.
There is an enforced dress code, meaning you will be required to wear dressier clothes than you might normally wear out in LA. The bouncer the night we went was turning men away for not having dress shoes (leather and devoid of any design asthetic that could make them seem remotely athletic or casual). I would definitly avoid wearing jeans or cargo pants also, although this particular bouncer seemed to be less strict on this matter. Not sure of the requirements for women, but almost all were in cocktail dresses and high heels.