Accidentally hitting the wrong key or mouse button at the wrong time can be a giant pain in the butt - for example, when it causes you to tab out of your favorite FPS just as you were about to pull off a sweet headshot.

It's annoying for kids as well. I can't count how many times I've been watching my son accidentally bump a button and cause his Flash-based game to lose focus.

Kid Key Lock is a free application that disable sets of keyboard keys and lock down mouse buttons and actions (like wheel movement or double-clicking).

It's not fully customizable, but it allows disabling keys by groups: none, all, just system keys, or all but space, enter, and characters.

In case you accidentally lock all keyboard and mouse functions, the program supports a password - which you can enter to override the lock or enter setup or quit the app entirely.

Kid Key Lock is also handy for when you want to give your keyboard a quick cleaning without shutting down first. It's a free program, and runs on both 32 and 64-bit Windows.