very handy GameTimer library

I put all the game timer code I use up on GitHub.  It’s super useful for doing stuff like speeding up gameplay, slowing down gameplay, hit pause, etc.

I’ve found that Timers in games are very hierarchical.  You’ve got the main clock, which is basically run off the cpu clock or whatever and never stops.  You’ve got a game clock which can be paused, or if the game is kinda sluggish or frantic you can tweak the speed this clock runs at.  Then you’ve got all the clocks that run off that, including character clocks, particle engine, physics clocks, etc.  If these are run hierarchically, when you pause the main game clock all the ones underneath it pause too.

Also when playing a network game, can send those clocks from the server to all clients, and all the players will instantly be synched up. Very neat trick!

Anyway, this is the way I do it. From readme:

A bunch of timer objects that can be used for time effects like hiererchical time, slowdown, speedup, hitpause, etc.
The most important thing is that these timers can be used hierarchically. You can pass one gameclock into the update function of another one, which updates based on that dude's time. So the timer chain might look something like this:
/ | \
Character1Time ParticleEngineTime Character2Time
So like the MainTime is a GameTimer.GameClock and is updated first from the XNA GameTime object. This one always runs at realtime, so you don't want to pause or slow it down. Can problably run HUD or menu transitions off this clock.
The GameTime is also a GameTimer.GameClock and would be used to run the gameplay itself. This one can be paused for the Pause menu, or slowed down/sped up if the game play speed needs to be changed. Since all the clocks below this one are updated off it, they will also pause/slowdown/speedup.
Under that, you could have the ParticleEngine running off it's own clock separate form the player characters. That way when the players are punching the snot out of each other, you can add some hit pause to add crunch and the particles will still be flying around.
Idunno, that's just example how I use it in my fighting games. I also send these timers over the network to sync up the server & clients.