Was just reminded of this by a post I saw elsewhere-and I don't think it's come up here recently.

Most dice that come with games are made extremely cheaply-leaving a number of imperfections that will sometimes cause a significant bias in the way they roll.

I know some people use apps or the like to calculate the rolling, but for anyone still rolling real dice this can be annoying.

There are a couple of good videos here regarding how/why this occurs: http://www.gamescience.com/ (Yes, he's trying to sell you his own dice there-I haven't used that brand, but the videos are good).

Personally, I still play with the original dice in some games, but I have a pair of precision machined backgammon dice (used for gambling-so they make it to a higher specification) that I'll use for a lot of things.

Just an FYI for those who might not have known this.