A die with infinite sides would appear to the human eye as a circle. Since each side would have to be such a small shape and size to accommodate the infinite other sides, we wouldn't be able to make out individual sides, thus seeing a circle. If you roll a marble or other type of circular ball, it eventually comes to rest, doesn't it? The momentum you put into the ball eventually runs out, it just takes longer than a traditional die. So yes, you would eventually get the die to stop on a number. Edit: this is hypothetical, ignoring the fact that it's impossible to have infinite sides, and that in order to have infinite sides, the die would be infinitely large, require an infinite amount of space, and we wouldn't be able to read the numbers as each individual surface would be too small.