I use scripts for the following:
1) (Windows) When developing software I always use a very restricted user account to host the development environment. However that also means I won't have admin access to critical components, like Visual Studio, so I have a BUNCH of scripts that enables me to shutdown as an admin (restricted users can only log of win2k3), launch various programs as an admin, launch our product as various test users (with differing rights), and so on. Very handy!
2) (Linux) When running a heuristic or an algorithm for research uses X number of times, I used a bash script to repeatedly run the algorithm, and to save the results in the appropriate locations.
3) (Unix) Back in the day, when I was playing RPGs online (So called MUDs - Multi User Dungeon), I used scripts to launch automated sequences that I did frequently. That never ceased to amaze the other MUDers that complemented me on my insane typing skills.
4) (Linux/Windows) I sometimes use scripts during logon and logoff, and whenever various events are raised on the computer (like remote users logging onto my OS!).