Hey everyone ! I want to know if it's possible & how can I assign a note of my keyboard(midi) that will Bypass/Active a plugins (Even if i'm not in sonar, like in a game)
 
Thanks ! 

keyboard instrument or keyboard as in (I type on my keyboard = qwerty keyboard ) ?
 
you can probably find a keyboard shortcut in preferences/ keyboard shortcuts.
look for a key to match it for bypass FX

you need to assign MIDI command to the specific feature, then it should work even when you'll have different program open in front :)

It depends on whether the plugin supports automation for bypass. Many do not. Those that do can be "trained" to respond to a MIDI CC. It's unlikely such a technique would work inside a video game, though. There are, however, general-purpose USB MIDI devices that can be programmed for many non-musical functions, such as scrolling Word documents.
 
Here's an example.