D.P.
How about taking the blocks away. Abstract punishments like time-outs don't work that well with a two-year-old in preventing repeat behavior. What they do is stop the immediate behavior, which is important. Blocks are not for throwing--period (not even soft blocks). It's dangerous and could break the TV, then he couldn't watch anymore. You have to be consistent. Discipline him EVERY time he does a certain thing (throwing blocks for instance). Eventually it will sink in.