I have a pair of odd six-sided dice at my house... I don't quite remember where I got them.
Each die has only one number on each side, and each of these numbers is a positive number.
Each pair of opposite faces sums to the same number on each individual die (but not necessarily the same across both dice)
Furthermore, the two dice, when rolled together, have the same probability of coming up a certain number as two six sided dice coming up with the same number.
Here are my drawings of three faces from each die:
(the 6 on the top drawing is actually a 6)
To solve the puzzle, all you have to do is:
Draw a complete cube net of each die.
Good luck and happy puzzling!