Although technically in Hollywood, this is the closest men's bathhouse to the Santa Monica Boulevard GLBT nightlife action in West Hollywood. Melrose Spa
(7269 Melrose Ave., 323-937-2122) is part of the Midtown Spa gay bathhouse chain, which has two other locations in the Los Angeles area (Midtowne Spa in downtown L.A., and 1350 Club, in the city of Wilmington - down near San Pedro and Long Beach).
For more on gay cruising and sex clubs in the region, check out the Los Angeles Gay Bathhouse and Sex Club Guide as well as the San Diego Gay Bathhouse and Sex Club Guide.
If you're headed up north, check out the San Francisco Gay Sex Club Guide