Under the application properties you can edit the hotkeys for things like that (under 'menu' or something) if you want to use MMF's default pause thingy.
Of course, default pause looks cheap. It looks better to program a custom pause function. Toggle a flag when pressing the pause key, and when the flag's on disable the groups related to movement, animation, collisions et cetera and stop the animations.
- Ok, you must admit that was the most creative cussing this site have ever seen -