Replaced an ahead headset on my GT Tempest, using a small and large screw driver, one length of copper pipe, a hammer and a piece of wood wrapped in a rag (so as not to wake the missus)...
Worked a treat - although she woke up anyway.
Trickiest bit was removing that little wedge of plastic, which I chewed to bits, it has to come up, before the fork drops down... fettle finished before midnight (new PB!)