Interaction between humans and virtual agents is becoming increasingly prevalent. This research investigates the influence of virtual agents on users' opinions within a virtual stand-up comedy club setting, focusing on the socio-psychological mechanisms of emotional contagion and group conformity. We aimed to combine these two areas in a novel study approach. To this end, we designed and conducted an exploratory pilot study in which participants ($\mathrm{N}=20$) rated the funniness of jokes in VR, under varying conditions of virtual agent laughter (absence, medium intensity, strong intensity). Our analysis shows a significant positive linear effect on the log odds of higher funniness ratings when virtual agents exhibit laughter. Moreover, our study shows that this effect is mainly due to emotional contagion processes, individual differences in susceptibility to group conformity, and the interaction of both concepts, showing that emotional contagion happens only when the individual susceptibility to group conformity is high. The results offer valuable insights into the social impact of VR environments and the potential of virtual agents to shape user perception and opinion.