The Zeus Video Player script allows you to play AVI files in RPG Maker XP, VX & VX Ace and choose to resize them to the window size of your game or to set a background image while the video is playing.

When a character counterattacks they always use the default attack command.

Here's a tutorial on how to make counterattacking use different skills upon being inflicted with a state in VX Ace.

Here is a tutorial on how to show windows message boxes through a script call in XP/VX/VXAce

Here's a tutorial on how to script a discount in shops that activates upon a switch in VX Ace: