When sending a sms on my cell phone and I select the person it is going to when the address book comes up I hit "j" and it then only displays names that start with "j". Even though 99% of the time I select my wife "Jen" it never pre-selects it by default, but the first one in the list.
When running a set of auto-tests remember what has failed before and runs them first.
Exiting examples (that seem almost revolutionary):
When launching your browser rather then showing a blank page show the most common page people go to.
When compiling a projects rather than preprocessing things over and over store them for reuse on the next file to be compiled.
-precompiled headers (in some compilers, new for gcc 4)
Remember what TV shows I watched in the past and if there is free hd space and I am not doing anything and I have never seen that episode of the series automatically record it for me.