I found some great math lesson plans at C.R.E.A.T.E. for Mississippi. The lessons I have looked at set the grade range at upper elementary and middle school, but I think you could easily implement them with younger children by letting them use a calculator and helping them in some areas. In fact, I will probably even let my older children use calculators. I won't be using the lessons to work on arithmetic skills, but to give my children a taste of math in the "real world."
In Go for the Gold Part 1, the student does web research on countries participating in the 2002 Olympics and learns how to figure percent, enter data into an Excel spreadsheet, and create circle and bar graphs in Excel.
There are 51 lessons, a few of which include carpeting your castle, traveling to the end of Pi, and NBA math. There is even a chicken mummy project that integrates math. Too bad we're about done with ours.
This would be a great way to liven up your math studies and give your children a taste of what you can really do with math. If you don't have Microsoft Office and you want to use the lessons using PowerPoint and Excel, I highly recommend OpenOffice. This is a really great (and free) office program that will open and save in Microsoft format. I tried out some of the the Microsoft Word and PowerPoint files from C.R.E.A.T.E. on OpenOffice and had no problem opening them.
Living Math! has some really great ideas for looking at math differently. I still use curriculum, but I am also learning to delve into different areas of math without being afraid that I am going to ruin my kids.
The C.R.E.A.T.E. site has lessons for other subjects also, but I haven't checked them out.