The asynchronous processors attack clock-related timing problems by asynchronous (or self-timed) design techniques. Asynchronous processors remove the internal clock. Instead of a single central clock that keeps the chip's functional units in step, all parts of an asynchronous processor (e.g., the arithmetic units, the branch units, etc.) work at their own pace, negotiating with each other whenever data needs to be passed between them. In this paper, several projects are presented, two of these -- the Superscalar Asynchronous Low-Power Processor (SCALP) and AMULET -- are presented in more detail.