There are hundreds of clubs, including Club Ai, Club Clover, etc etc etc.
The film follows the then-22-year-old club owner Issei, coupled with interviews from his staff of 20-something hosts and several of his (very pretty) clients. If you get the chance, watch it (it's on Crunchy). The story-telling is fluid and the honesty of the hosts (if you'd believe it) is refreshing. Issei's frankness about how fucked he is (liver-wise and psychologically) is funny, and very telling of the fantasy world these men-for-hire have to constantly create to satisfy the needs and dreams of the women, who can spend up to USD7,000 a day.
In the end, while there's a sense of tragedy that the entire situation is an endless cycle of self-loathing and 'soul healing', you can't help but hope that both the girls and the hosts find a way to ultimately be happy.