Cobra Marital Arts
The Cobra Martial Arts is a gym located in Garcia, San Fierro. The gym becomes accessible after the mission Drive-Thru, however, Carl Johnson will only be able to access the gym without police attention following the mission The Green Sabre. Carl Johnson can learn some martial arts moves, as well as use the other facilities to increase or decrease certain statistics.
Joke
Another one of Rockstar Games jokes, instead of M-A-R-T-I-A-L it is spelled M-A-R-I-T-A-L, probably as a reference to "Marital" as in "Marital status".