You can buy an anti-static mat, which is usually used for computer service work, and has a wire to the ground conductor (earth, for the UK audience) of the AC plug-in (mains). If you put your PB on one of these mats, and touch the mat before the keyboard, you should be fine.
Bad things to touch when at a static potential would be any connectors or leads, such as Flash memory cards, RAM modules, USB or firewire connectors.
Thanks
Trevor
CanadaRAM.com