An easy infinite (well, PP limited one, though you might be able to get a recharge setup with link and dominant ideal in there) is sharing it with your psicrystal. You use your prepared action to cast synchronicity, it is metamorphized into a nasty form and attacks something. Repeat ad nauseam for one free attack/powerpoint (possibly a little worse, if you need to augment it to get different actions for you and your psicrystal).
Correct, now an easier version of this is as follows
You manifest Synchronicity with 3 pp. When you manifest Synchronicity at 1 pp you can pick any standard action and both you and your psicrystal can do the same action, since you share your power with your psicrystal and at 1 pp you pick the action when you manifest the power. Now when you spend 3 pp instead of 1 (augmenting it via 2) you don't have to choose the standard action you are going to perform until you actually do it, give you (and thus your psicrystal freedom).
So this is what happens
Cause 1) Manifest Synchronicity at 3 pp
Effect 2a) Synchronicity gives you a readied standard action which you can use immediately. You use your standard action to manifest another Synchronicity go to Cause 1) again
Effect 2b) Synchronicity gives your psicrystal a readied standard action at the same time. The psicrystal uses his standard action to do whatever with. Lets assume you prebuff your psicrystal with energy conversion, allowing your psicrystal to shooti ray (which must make a ranged touch attack) if the ray hits it does damage equal to 3*Your Manifester Level.
Thus while you still can cast 3pp a round you give your psicrystal freedom to do whatever it wants that only takes a standard action to do. Give your psicrystal some unlimited ability like energy conversion (or the ability to teleport as a standard action, and thus move and attack) and you will give your psicrystal a lot of extra turns.
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The more powerful version of the shuffle is when you throw dominant ideal in the mix and thus starting round 2 (or the same "effective round" with temporal acceleration) you get those extra standard actions allowing you to kill the enemy with way too many turns. See here for more info.
http://brilliantgameologists.com/boards/index.php?topic=7385.0