If you need to give your keyboard a quick wipe-down, you can use child lockers to temporarily shut it off instead of restarting your computer entirely.
Every once in a while, your keyboard gets a little grimy and needs a quick cleaning. Of course, you rarely realise this when your computer's off, and it's not really worth restarting since it's a 10-second job. If you want to clean it without pressing a ton of keys, just use a key locker like previously mentioned Kid-Key-Lock -- it's portable, so you can start it up just for a few seconds while you wipe down the keys. It also locks your mouse and drive doors, so you can give your whole machine a quick cleaning without turning it off.