Ep 7 - Is Foolishness Sinful? + Gambling

Is everything that the Bible describes as foolish a sinful thing to do? This question come up recently and we thought it would be fun to talk about. 

The natural outflow is to give an example which is why we then ask, is gambling sinful? The Bible certainly sees gambling as unwise, but doesn't outright condemn it as sin, so should we avoid it or is it occasionally okay?