The turbo newbie is a tactic often used by Terran players in the game of Starcraft when there are unaccessible areas of high ground- usually cliffs and/or islands- near an opponent's expansion. The strategy was originally named as such because it was one that even someone new to the game could execute without much problem. One dropship, carrying a cargo composed of one Siege Tank, an SCV, and three marines moves as quietly as possible to the cliff area behind their mineral line. The Siege Tank moves into siege mode in an opportune place, while the SCV quickly constructs a bunker for the marines to hide in, often accompanied by a missile turret. The siege tank decimates a worker line from afar with its long range, and opponents are often hard-pressed to get rid of the tank without siege units of their own. Small amounts of Wraiths and Mutalisks are likely to get destroyed by the combination of bunker and turret fire, and other ground units that aren't dropped directly on the cliff have to deal with a general inaccuracy problem compounded by the fact that the tank is often far enough not to be hit by multiple units at one time. Variations on this strategy can be utilized by the Zerg player with Lurkers, or by the Terran player adding more dropships to the mixture.
While this is a potent denial technique, it will not win games by itself- all it can do is stop an opponent from using that expansion until they can tech to siege units of their own and nuke your setup from the air... that is, of course, if you let them. Turbo newbies are usually followed up on the attacker's part with an expansion of their own or an attack elsewhere on their opponent's base- as the TN setup is usually self-containing, it is less micro-intensive than other Terran strategies, letting you concentrate on the tank push elsewhere.