Millennium Club is located within Cavern Club (4 clubs for the price of 1, see the link above). The crowd here is pretty random, rather than consisting of a certain age group or ethnicity as some clubs do. The perks are cheap drinks and the widely varying crowd. If you're a people watcher, you'll like watching all the different types that come into this bar.
The DJ spins the sounds all night to keep the dance floor grooving, and you'll enjoy watching music videos on their multiple television screens. Their nightly drink specials are a definite hit.