Dave, fist of Odin
Hey Rob - you know it defaults to 3 dice of the type you want to roll, yes? You have to tell it to just roll one.
I don't know if that's the issue or not - I'm just saying. I've never got a roll that weird.
Oh - and I'm angry now. I roll to hit and smack a non-wounded bitch up! I roll a 15.
Hmmm . . . now I'm suspicious . . . let me pull out a d20 . . .
Well, on my actual die, I roll a 15. No lie. Odin is guiding my hand!
And repeating the rolls, I got about a hundred numbers all between 1 and 20, inclusive. Seems like a fairly good distribution, too. Maybe it's your browser - are you just using a telnet client?