Blow Money

When budgeting for your family, one of the most important categories you can include is the Blow category. This is your personal "miscellaneous items" category, which gives you the freedom to spent money spontaneously and spend money on yourself. In our household budget, we have four blow categories, one for my wife, one for each of our daughters (we have 2 kids), and one for me. We have decided to be generous with this blow category, because it also serves as a personal clothing budget.
For some of our household budget categories, we withdraw cash at the beginning of the month for categories, such as food, where we would walk into a store to spend the money. This allows us to easily see how much money is left in our budget for specific categories at the end of the month. Each of these cash budget items has its own envelope. When we go to buy food, we take the food envelope or a few bills from the food envelope with us.
I usually carry $20 or $40 of blow money in my wallet. This gives me the freedom to go out to lunch during the week. It gives me the option to pick up milk on the way home if I don't have our food envelope with me. It allows me to buy a new music cd or electronic device.
As stated earlier, our kids have their own blow categories, but that money is not an allowance. Their blow money is more of a clothing budget. When one of them needs clothes, that's the budget category the money comes from.
One thing that the blow category does well is it helps you keep the rest of your budget on track. For example, if there are a couple of days left until your next paycheck and your entertainment budget envelope is empty, and you haven't spent all of your blow money, you can still go out to the movies.
What are your experiences with your blow money? Please post in the comments below.