"You can accomplish whatever you put your mind to" holds a bit of extra meaning for you psionics-players out there. Different from magic, psionics allows characters to use the "power of positive thinking" in order to change the world around them. In this installment of Unearthed Arcana, Wizards of the Coast expands on the Psionics class.
First off, you can now get your Psionics characters to level 10 (ding!). They've also made the class more flexible. There's a single discipline that you can choose to gain a constant bonus from, while still letting you spend psionic points to use abilities of any discipline you know. Just like magic has their cantrips, psionics now has low-level psionic talents that you can use most of the time. Finally, psionic disciplines are available to all mystics now, making it easier for your characters to dabble in the power of their minds.
As usual, things in Unearthed Arcana are sort of in "open beta" format. They're free to use now as you like, but not in official events. They'll eventually be refined a little more and published so they're fully official, but that might be a bit down the road.