This episode is a sidestory!  Gintama has been involved in many (one-sided) crossovers.  This time, they're working with the Jump comedy manga Sket Dance!  An episodic anime that airs on Thursdays at 6 PM about a group of three odd jobbers with plenty of laughs and tears...  Sounds very similar to Gintama.  As Gintoki warns that the Sket Dan is coming after Gintama, the Sket Dan members appear and offer a challenge!
Indeed, their weak will is 
embodied by their weak goals.
Ciertamente, su débil voluntad se manifiesta en sus débiles objetivos.
Realmente, a falta de força de vontade 
deles se reflete nos objetivos baixos.