D.S.
My 4 year old loves to do workbooks. We find a good variety at Target - Preschool/Pre-K (and other grades) big books, mazes and dot-to-dot based on age, letters, numbers, math, sight words. We got our favorite one from Aldi but that was last year and I think they only carry them around the start of the school year. CVS sells some, too. We also have some specialty toy stores around here that carry great selections with knowledgable staff to help you pick the right one. You might see if you have something like that in your area. Ooh, and science or kids museums! Every one has a gift shop, right? :)