Jesse pointed out this great offering for aspiring BlackBerry 10 devs from BlackBerry. BlackBerry has posted up 35+ interactive training courses for BlackBerry 10 Cascades and WebWorks concepts. They walk you through a session in 15-30 minutes with exercises you can download and play with yourself. You can even take the quiz afterwards to test your retention. These courses are also useful if you are studying for BlackBerrys new Certified Builder exam for developers.
Right now I count 35 training items with more listed as coming soon. They also plan on releasing more when the BlackBerry 10.2 Gold SDK release along with updating the current ones.