setting up an encounter before actually arriving in rio de janeiro cen be a great idea -  interacting with the locals can transform the way one will experience and understand rio, and if done properly, friends will be available for the rest of the vacation. 

brazilians love to gather in groups and connecting with a gathering of cariocas is a great way to meet new people - cariocas generally know what events are taking place, such as parties, concerts, and other musical or cultural events, so their information is invaluable - festivals, art galleries, free concerts, and social gatherings happen on an almost daily occurrence in rio de janeiro.