K.L.
I have a very active 19 month old, and I stay at home with her while working full-time out of my home (I am currently a nanny to an infant girl) and we definitely have those days of PBS and Sesame DVD watching maybe two times a week - it's okay to plop your little one in front of some educational TV for an hour or so while you get done what you need to do around the house. I'd never get any housework done if I couldn't sit the kid in front of Sesame for a hour or two so as not to bother me while washing the kitchen floor or cleaning the bathroom, so don't feel bad at ALL about that! I found myself in the same situation as you when my daughter turned about 1, and was really eager to get out of the house.
Your two year old is now becomming more creative than he ever has been, so utilize those skills to keep him busy - take out some old magazines, a glue stick, and a piece of construction paper and make a collage of animals or people (some theme). Fingerpaint, build things with play-doh, create a story on a piece of paper with stickers of his choice. Take simple "nature" walks around the neighborhood and collect different leaves and flowers and inspect them when you get home - point out the birds, the bugs, the cats, anything that you see around to create conversation. I take my little ones to the park at least twice a week so that they can get some socialization with the other kids (and it gets em good and tired). Sometimes I give my daughter a bath at an unconventional time of day to mix things up. We go to the grocery store and I let her hold all the fruits and veggies while we talk about them - when I want to get a starbucks coffee, I get her a cup of milk in a starbucks cup which keeps her busy and happy.
You just have to use your imagination to bring a little more fun to things that you might do everyday. Call on your teaching skills (I am a teacher as well) and do things with your son as you would with your students - expand on otherwise boring or monotonous tasks to make them fun. Go to the nearest bookstore and let him pick out some books for himself. When I was a kid I loved it when my parents let me make "concoctions" by putting all sorts of different spices from the spice cabinet in a bowl of water (keeps em occupied for HOURS). Be creative, but dont think you have to go so out of your way to make things fun ;)