The performance style seen in this episode is called "street dancing", an umbrella term that describes many different sub-groups of dancing. A lot of these forms of dance are now taught in dance studios.
The specific form of dancing seen here, that Mac Taylor (Gary Sinise) says he thought "went out with Ms Pac-Man and the Rubic's Cube" and Stella Bonasera (Melina Kanakaredes) says went underground, is called "Break Dancing" and is a professional form of street dancing.
The specific form of dancing seen here, that Mac Taylor (Gary Sinise) says he thought "went out with Ms Pac-Man and the Rubic's Cube" and Stella Bonasera (Melina Kanakaredes) says went underground, is called "Break Dancing" and is a professional form of street dancing.