There are. Probably the #2 most popular coin is 'litecoin' (http://litecoin.org/ http://litecoin.org/). It uses scrypt instead of sha256 in order for it to be h

There are. Probably the #2 most popular coin is 'litecoin' (http://litecoin.org/ http://litecoin.org/). It uses scrypt instead of sha256 in order for it to be harder/more expensive to use GPU clusters and FPGA/ASIC hardware to mine them. Mining using GPU is still somewhat quicker/more efficient than CPU, but the delta is much less than exists for bitcoin. There are other coins as well, but I'm less familiar with them.