I agree about moderation. Or, I vote for modification.
In that case, I would do one of two things:
1. Eat a piece of pizza or two, and have a small sliver of cake. I'd also eat a calorie-light breakfast and lunch to make up for the excess calories.
OR
2. Make yourself a healthier pizza! A
homemade pita-pizza seems like a decent idea. If you're just making it for yourself, and the kids are taken care of with takeout-pizza... might not be too much trouble.
And then, either indulge in a small slice of cake... or find yourself a sweet alternative that you still love. Low-calorie frozen yogurt with blueberries, or Skinny Cow frozen desserts.
Whatever you decide, it'll be fine! Just go back to eating well afterward, and you'll be right back on track, even with a small jump in calories!