I spent two nights wandering along the famous strip without gambling a single dollar, and never once got bored.
The scale and variety of the casinos is almost incredible. I explored the casinos along South Las Vegas Boulevard from the pirate-themed Treasure Island to the tropically-inspired Mandalay Bay. Between the two is a casino inspired by the Romans (Caesar's Palace), casinos inspired by modern Europe (The Venetian, and Paris Casino), a casino that tries to fit an entire US state into one resort (New York, New York), a casino born of Hollywood (MGM Grand), a casino that tries to capture the spirit of medieval Europe (Excalibur), and a dark and brooding casino inspired by the ancient Egyptians (The Luxor). Plus several others that aren't as easy to describe.
Many of the resorts are so clearly aimed at enticing tourists and families inside that it seems at first as if they aren't bothered about luring in serious gamblers. But the serious gamblers apparently don't notice or don't care what's built-up around the gaming areas, and even in the very small hours of the morning you will find pasty-looking men and women staring at cards, dice, and video screens. In almost every casino, windows are a rarity and it's nearly impossible to tell what time of day or night it is once you're inside the gaming area.
I was lucky enough to stay in the Rio All-Suite Hotel & Casino without paying, because the person I travelled with was a regular there. The Rio is very close to Caesar's Palace, but is not actually on the main strip. In fact, when I tried to walk from the strip back to the Rio, I got very close but eventually had to turn back in failure. The sidewalk ends suddenly and the road becomes too dangerous to travel on foot. I had to return to the strip and take a taxi. Like most of the US, Las Vegas really isn't designed for pedestrians.