Sure you can
Some set-ups are better for multiple viewers than are others, but it's certainly possible.
As TB says, you can hook an HDTV up to your computer using a standard monitor cable, which works great. Add some speakers and you're in business.
PS. My wife and I have become totally hooked on 30Rock. Why didn't someone tell us it's hilarious? It's great to be able to watch a couple of episodes at a time, whenever we want.