I'm going to talk about a something that I've found quite helpful with playing metric modulations etc. I call it Groove Surfing and it basically involves playing along with common time signatures (e.g. 4/4 and 3/4) but playing in odd groupings rather than the originally presented feel. This came out of my wanting to use odd groupings (septuplets, quintuplets, and the like) more in my playing while still hearing the original time feel and being able to go back to it easily. It's pretty simple. Just play along to any music where the the pulse is stated very obviously. Most classic Rock or Dance music works well. Then just add whatever grouping you're working on. You can play it as a beat or fills, just on the snare drum if you're having trouble hearing it, or any combination of the above. To give us some possibilities, here are some ideas I've been working with lately.
Okay, some explanation is necessary. None of these examples use all four limbs. I wanted to use some examples where the instrument is orchestrated. In example 2 I like playing it with only left hand and right foot and doing the opposite for example 3. Now, what about those question marks, has Ted finally flipped? Nope. What I'm doing is purposely not telling anyone who reads examples 2 and 3 (myself included) where I should play on the question marked beats. There is no "correct' place to play at those points. In fact, try to play the question marked parts on a different part of the kit each time you play it.
Now here's me playing along with the radio using each one of the examples. I hope Katy Perry's (or whoever's) lawyers don't get after me!