My day:

Free play/arrival of kids
circle time - Calendar, weather, felt board activities, finger plays, story time, etc.
morning snack
Art or learning activity
Free play/outside play
lunch
Quiet time
Snack
Group activities/Free play/outdoor play

Learning activities include science activities/experiments, math, fine motor skills activities (like cutting, tear, gluing, scooping) and sensory bins (sand, water, etc). These can be created/adapted to suit a wide range of ages.

I do different things each day of the week - Monday is Art, Wednesday is Science, Friday is Sensory Bins. I leave Tuesday and Thursday as more of my variety days, they could be math activities, fine motor skills activities, etc.

I really like the following website, it has lots of great ideas and it doesn't involve a lot of prep for you...

http://www.preschool-plan-it.com/preschool-themes.html