Perhaps the first order of business would be the falling tree leaves. Mowing several times a week will recycle leaves back into the lawn. Shredded leaves also make great compost and mulch. Lawns will certainly enjoy the unseasonably warm period of weather. Spot treat lawn areas to stop broadleaf weeds.
Chickweed is growing like crazy in some lawns, not to mention a whole host of other broadleafs. Annual core aeration in the fall is the ideal way to improve the soil and control thatch.
After this warm period there are a number of insects and spiders that will be looking for winter quarters. Caulking cracks around the outside of the house is a good place to start protecting your home turf. Once indoors Ortho Pest Control does a nice job of eliminating unwanted bugs. The ground is pretty well saturated with water, but it will be drying enough to plant by mid-week. If your local garden center or nursery has it, plant it!
Vegetable gardens can be cleared and planted with ryegrass for a cover crop.