A "vpiska" is an informal party that usually takes place in the apartment or house of one of the participants. Participants can be friends, acquaintances, or even people who are not well-known to each other.
Often, a vpiska does not have a clear script: people simply gather to chat, listen to music, dance, eat, or drink. An important feature is the possibility of staying overnight, which distinguishes it from a regular party.
The word "vpiska" comes from youth slang, where "to vpisatysya" means to join someone’s residence for a temporary stay, usually for free. Later, the term spread and began to mean the event itself.