This post is high-nerd-content. Consider yourself warned.
I was thinking today about how we live in a joint binary/decimal world. It manifests itself in all sorts of ways that are easily overlooked. Take, for example, the fact that a 25th anniversary is often made into a big deal. Why 25? It isn't a product of 10, which is usually the period over which annual events are especially commemorated (c.f. last weekend's 60th anniversary of D-Day). 25 is special, of course, because it is the quotient of 10 squared divided by 2 squared. It arises from combining our two favorite counting systems.
As Scott will tell you, there's a long-standing fight in this country between the older base-2 measurement system and the base-10 metric system.