Depends on what you're watching. I can, but not every one can sit through a test match. It's just a very tough thing to do. ODIs? Easier to watch, for sure. T20s? Now those are four hours of fireworks...and if you're bored later this summer the World T20 will be on WatchESPN...
Don't some games, matches, whatever, go on for days?
The Test matches do. They can last up to five days. There used to be a format called a "timeless test". Those could theoretically go on forever, but they were scrapped a few decades ago.
ODIs are usually about 8 hours-so be prepared to give your day up. Bright side,if you go see it live, they usually have a lot of berm seating...so you can tailgate practically all game I'd assume (haven't had a chance to go to a game). There's actually a full sized international standard pitch down in lauderhill, about an hour north of Miami. the U.S. usually plays it's Auty Cup matches against Canada there. You also sometimes see an international match there every couple of years-usually a T20I, and they hold them on back to back days. The West Indies played New Zealand there last. THere was talk of a Pakistan-West Indies series there but they couldn't get the visas cleared in time last year.
T20s (also known as twenty twenty) are 4 hours long at most. They're so short that it's a constant climax the entire game. Huge shots, tons of scoring, sudden changes in momentum...it's not dissimilar from watching an Arena football game. Most people think the T20 format is the easiest to export to the United States, but as you can guess, it hasn't really taken much hold, mostly because our national team is awful.