Begin each week with a theme that you tie into each day's subject of study. For preschoolers the topic Animals is always a hit. Incorporate this theme into a simple math lesson with a counting exercise involving pets. How many and what sort of pets does each student have? Sort and count them by type, by age, by color -- the possible groupings are extensive, and students can get some beginning addition practice here as they record the numbers of cats, dogs, gerbils and fish that each student (and the classroom as a whole) has at home.
Continue your Animals theme with a look at some stories written about animals. Eric Carle has a number of popular books about animals that are perfect for preschoolers. There are also plenty of books about animals who walk, talk and act like humans (the characters "Little Bear" and "Francis" are two examples). Ask your students how realistic they think these human-like and fancifully drawn animals are. List with your students all the human characteristics that they find in each character.
Begin this day's lesson by looking at the real characteristics of the animals from Tuesday's stories. Alternately, you could take your cue from the time of year. Again, tying the theme of the week to the calendar will help ground the topic in place and time for the students. If you have a large window in your classroom, have the students spend 5 or 10 minutes looking outside to see what animals they notice out and about. Better yet, take your students on a nature walk and have them collect any signs or sightings of animals. Record your classroom's findings and retain these records for use in comparison once the season changes.
Social studies as a school subject is simply the study of the culture and people of the world, and the Animals theme can fit nicely into a social studies lesson. Choose an ancient culture which had a high regard for animals (Native American tribes or Ancient Egypt are two good choices) and share some stories and myths from these cultures that involve animals. Discuss with your students why animals might have played such an important role in these cultures.
Why not make Friday a special event or "freaky" day devoted to practicing a sport, taking a field trip or creating a special art project? Friday would also be a convenient time to tie everything you've done during the week back to the calendar. Talk about seasons of the year, phases of the moon, holidays or any other calendar-specific topic that is current. Review your week's theme of Animals and see what awesome facts your preschoolers remember.