The closest thing to a Lesbian Club...
The Cobalt
Why locals love it
Vancouver does not have a lesbian bar, and this is the closest thing you will find to it in the city. However, there is a great mix of gay/straight/bi/ect girls/guys/others in the city. It is relaxed, fun, and unpretentious (but, at the same time, they play awesome music). They have lots of shows, and bands, playing too.
Why you should visit it
If you're looking for a really chill, and accepting, place, the Cobalt is it (notably, if you're in a gay/straight mixed group - there's something for everyone here!). It's not somewhere frequented by tourists, and you'll get a real feel for the East Van nightlife (without creepy people giving out undesirable grabs).
Special tip
Call ahead to make sure there's no special event, or what the situation is for cover charges for that night; if there's an event, it can be pricy.