I have quite suddenly found myself with a toddler in my home (my sweet baby is growing up), and I have absolutely no idea how to handle this. Help!

Here's the problem...

My daughter thinks it's hysterical to throw (and I really do mean throw, not just drop) any food that she doesn't like on the floor. When I tell her "no" she laughs at me. When I take her hand and place it on the table and say food is not for throwing, she laughs at me. When I pull her high chair away from the table for a 60-second time out from dinner she has no idea what is going on, and she often laughs at me again. As soon as I let her get back to eating, she resumes throwing her unwanted food on the floor. I think we need to promote a little bit of discipline in this situation, but I don't really know where to start. None of my attempts are working at all.