Wow you've got the exercise thing down!  I don't have any kids or pets, just a husband who's easy to keep up with b/c there's only a few places in the house he ever is :)

Here's some more ideas for accidental exercise:

Holiday Decorations can take a lot of exercise if you want it to!  Do a real good job, take your time, and put a lot of effort into getting it all done in a few hours.  You'll be warn out by the end of it but you'll fee great!

Reorganize something in your house. Winter is great time for organizing.  You're stuck in the house for the most part, so why not reorganize?  If you got cabinets that are a mess, or maybe it's just your DVDs that are out of order, spend the winter organzing and you'll get a lot of accidental exercise :)