What can we lawfully do on Sunday?

From scripture it is obvious that the scribes and Pharisees over did it. Sabbath is made for man and not man for the Sabbath. People can prepare food on the Sabbath, "pull ox out of pit" i.e work if it is necessary to keep a job which you need to provide for your family (He who doesn't is worse than an infidel) etc. But what about buying things, or going to see a movie at a theater on Sunday? Some people might consider paying for tickets, or buying food, encouraging people to work on the Sabbath because they would know that they could get customers. What about just watching a movie at home...? Is that wrong? Why? Why not? Please use scriptural proofs to support your answers.

Thanks,

-Karl-