The website Londonist has published an artcle on “6 Debauched Parties We Wish We’d Been Invited To”. These are all from the Bright Young People days that were described in Waugh’s novel Vile Bodies. There is one which involved Waugh directly:

4. The Bruno Hat exhibition party (23rd July 1929, Buckingham Street)

A mysterious art exhibition in July 1929 brought guests ranging from Lytton Strachey to Winston Churchill to a house in Buckingham Street, where the work of emerging artist Bruno Hat was celebrated at a cocktail party. Evelyn Waugh had written the catalogue for the exhibition and many guests spoke admiringly of the work on display. However, the next day revealed the truth: ‘Bruno Hat’ was a hoax dreamed up by Brian Howard, an ambitious member of the Bright Young Things who longed to throw his own legendary party. Waugh, Strachey and a number of other people were well aware of the charade. The event was described by the Daily Express as an “amazing hoax on art experts”, with the ‘artist’ at the party actually being Tom Mitford in disguise. We’ll level with you — we think some of the hoax art’s pretty good.

The story includes an interesting set of photos from The Graphic which illustrate some of the paintings as well as Mr Hat himself. Among others included in the Londonist’s selection are a Circus Party and Bath and Bottle Party. Both of these are among those listed by Waugh in the well known party paragraph of his novel which was published in January 1930 (CWEW, v2, p. 82).