Jimmy's home away from home, located underneath the clubhouse on the Neutron property there are several ways to into it primarily through the use of a DNA scanner that is attached to the clubhouse. Through the use of a single hair strand from Jimmy's head the scanner will analyze it and allow the person inside, this has been shown on many occassions notable example is Carl having a bag of Jimmy's hair to use to allow himself and Sheen inside, another is when King Goobot stole a stand of Jimmy's hair and used it to gain entrance. It is known that the clubhouse also has defenses against those without Jimmy's hair such as when Jimmy and Cindy were switched into each other's bodies, the scanner rejected Cindy's hair and Neutron who was currently in the former's body was kicked away from it.
Another route into the lab is through the use of an express tunnel located within Jimmy's room hidden beneath a poster, it is not used much due to the bugs not having been worked out during its use but it provides an extremely quick entrance into the lab.
Underneath the clubhouse
The lab itself had once been a basement years before Jimmy's birth which was shown when he, Sheen and Carl went back through time to convince Hugh to invest with McSpanky. After Jimmy had became interested in science, he converted the basements into a very spacious lab that leads close to the town's sewer system which provides a quick escape if the lab were to be inflitrated. The lab is also protected by several reinforced carbon steel doors that keeps all enemies out and is supposed to be nearly impossible to break through; even though it should be noted that Sheen has been able to penetrate them both, first with his distressed voice after his ultralord action figure was stolen and second when he was controlled by Grandma Taters but these could have just been a gag that was featured for the show as these incidents never have occured again. But on a whole, the lab is mostly used to help Jimmy's inventions and when he is needed to save his hometown from threats most of which are his fault to begin with.
The lab holds many of Jimmy's most impressive and dangerous experiments most of which are contained, such as the love potion, N-men power packs, Time booth, Jimmy's Rocket, hypnobeam and several other experiments that have either put Retroville in danger or are used to save it and more rarely to be used for personal gain by Jimmy or his friends.