There was a thread here recently about home buying and budgeting. I made note that every penny should be budgeted. I know not everyone agrees with that. That's cool.
I had an expense recently that I hadn't budgeted for and it was one of those surprising expenses that amounts to a small sum over the course of just a few weeks...
Greeting cards. I had never though to budget for that, but I had several reasons to buy them and they seem to just keep getting more and more expensive these days. My office mate had a birthday, my dd and dh had a birthday, Valentine's Day, our wedding anniversary, a death, and a wedding. I added it up, and for all of the cards, including dd getting dh a card and visa versa, etc... we spent almost $60 in greeting cards in February!!
That's not a big deal for us as we're financially secure, but it would have been a major blow to the budget 25 years ago! Obviously I would have been more cautious when I was just starting out and scraping to get by, but still. It's one of those odd expenses that you just don't THINK to budget for.
Any other ideas of odd things you have thought to budget for, but isn't usually on the budget radar?