Television and internet broadcasts of Mass are useful for the sick or those unable to get to Mass because of some other infirmity. If you were to miss Mass because you are purposely choosing to attend another event (say, a baseball game) that is a violation of the commandment to honor the Sabbath.
As the Catechism notes:
“You cannot pray at home as at church, where there is a great multitude, where exclamations are cried out to God as from one great heart, and where there is something more: the union of minds, the accord of souls, the bond of charity, the prayers of the priests.”
What is required is to gather as a Christian assembly of faith, not necessarily Mass, per se. There are plenty of parishes in the country, and many outside of the United States, that have no resident priest and therefore cannot have a Mass. They have Sunday celebrations in the absence of a priest, more commonly known as communion services. They read the liturgy of the Word and have pre-consecrated hosts from another holy sacrifice of the Mass held elsewhere.
Again, from the Catechism:
“If because of lack of a sacred minister or for other grave cause participation in the celebration of the Eucharist is impossible, it is specially recommended that the faithful take part in the Liturgy of the Word if it is celebrated in the parish church or in another sacred place according to the prescriptions of the diocesan bishop, or engage in prayer for an appropriate amount of time personally or in a family or, as occasion offers, in groups of families.”
In short, one should always set time aside to go to Mass and there are plenty of opportunities to do so on Sunday morning, Saturday evening, or Sunday night.