The Eleventh Doctor described the VJ Day celebrations marking the end of World War II as "one hell of a victory party". (COMIC: Sky Jacks)
Torchwood Three had a party on New Year's Eve, 1999. (TV: Fragments; AUDIO: The Torchwood Archive)
In early 2005, following the Dummy Massacre, Artie D responded to Doctor Who?'s request for sightings of the then missing Rose Tyler, saying that she looked like a girl he entirely failed to get off with at a party in Islington since she "swan off" after this other chap came up and said something about a different planet. (PROSE: The Doctor Was Involved in the Dummy Massacre)
On 28 June, 2009, Stephen Hawking held a party for time travellers at Gonville & Caius College, but he only sent out invitations after the event. (PROSE: Time Traveller's Diary)
In an alternate timeline, the First Doctor attended Chancellor Atrias' birthday party in the Urbinian capital city of Kiria. Afterwards, the Doctor brought a number of guests back to his apartment and they continued their high-spirited celebrations. Steven Taylor complained to the Doctor about it the following morning at breakfast for keeping him up all night before work. (AUDIO: Daughter of the Gods)
Iris Wildthyme and Panda once hosted parties in and around a village, specifically in a meadow and in the Village Inn. The village would soon after be destroyed, and Frank, one of around two dozen survivors, had flashbacks to these parties. (PROSE: The Party in Room Four)