One of the places I enjoy hanging out at since I've stopped working is the main branch of the National Library. It's convenient to get to, and the airconditioning is comfortable and not too cold like in the malls.
The wide selection of (free) books keep me entertained as well and the space is generally comfortable and pleasant to spend a few hours in.
Today, I've found myself a nosy nook to settle into, and I've picked up a Piers Anthony book which will transport me to the wonderful land of Xanth. What a wonderful way to spend a Friday afternoon!