equivalent of rooting/jailbreaking for blackberry.

Ok, so i just got a new phone (old phone..but new to me) It is a blackberry bold 9930 **Sprint**.

I have had an android in the past and i rooted it and loved it... was able to get any app and run custom roms...i have also jailbroken an iphone (i still hated it).

Now i have a blackberry and want to know what i can do with it...it is a little restrictive..so what is the equivalent of rooting/jailbreaking for blackberry and where can i find reliable resources on the subject...If it exists at all?

I appreciate any assistance.

 

still looking for answers! thanks guys