Cool soundboard
This is pretty funny. He reminds me of Bruce from Family Guy...
-Pros: It worked well. All the buttons functioned correctly. The spacebar command worked as well. The interface was easy to use as well.
-Cons: You got the sounds from a website. You didn't mention the guys name. The pranked dude didn't swear or anything. The link to the RealmofDarkness site didn't work.
-Suggestions: It would've been way more intuitive if you obtained these voice samples through your own prank calling (not that I'm saying you should) or a friends. It might have been more interesting if he'd gotten REALLY mad and started cursing up a storm. I guess that really wasn't in this guys nature. Make sure if you were trying to make a link to the RoD site that it works. If you weren't, make sure that you don't make it a button.
*It was a funny submission. I'll have to check out your other soundboards.