L33t Nekkid Skillz
The L33t Nekkid Skillz is a 'technique', for the lack of a better word, practiced by Largo when assembling computer hardware. Largo has a strong belief that the static produced by clothes can cause serious damage to the sensitive components used in computers and videogames. Thus, to reduce the amount of static generated, he casts off his clothes in order to avoid static discharge.
This practice is most likely derived from the anime Serial Experiments Lain, in which the title character is instructed to wear a nightgown while working on computer hardware to avoid static discharge. In real life, static discharge is a major concern when working with computer hardware, but it is usually mitigated by wearing special wrist straps, standing on anti-static mats and/or packaging components in anti-static bags, rather than stripping naked.
Largo's habit of doing this combines badly with Ping's "end user dress code" programming; she cannot look at him in this state, and eventually starts hitting him until he puts his clothes back on.
The only time when Largo has not stripped to assemble a computer is when he overclocked an Athlon in an internet cafe, when he offered to tutor Erika in computers to help her deal with incessant fanboy sites posting pictures of her on the net. While Erika compromised by changing from her usual cosplay uniforms to T-shirt and gym shorts, Largo seems to have retained his underpants. It also appears that Largo assembled a computer for Piro from components and a cereal box (presumambly an empty Crunchy Oaty O's box) left over from Largo's Beowulf cluster, while wearing all of his clothes, due to his massive hangover.