Why I love icecream:

$ (time make) 2>&1 | grep real
real    21m52.649s
$ make clean > /dev/null
$ PATH=/usr/lib/icecc/bin:$PATH
$ (time make) 2>&1 | grep real
real    8m15.954s

Note that about 4 minutes are spent linking the program, not compiling.

And then, while waiting, you can watch the hypnotic icemon showing where your source files are being compiled: