The Hub is perhaps Sacramento's best music venue you've never heard about. The location is secret, only members can attend shows and newcomers are invited by word of mouth. Once you attend a show, you've become an official member. A required $1 fee for first-timers adds your name to The Hub's e-mail list that will send you information about future shows. The Hub's four founders requested their identities and the location of the venue remain anonymous. Sunday night, a group of about 50 people braved the rain to see The Ganglians, The Fresh and Onlys and Woven Bones rock a packed Hub. Christmas decorations, a Persian rug and a homemade mural on parchment paper adorned the minimalist one-r