Dumb Dares
You don't necessarily have to buy a game for it to be a good dude game. Try a game of dumb dares. If there's one thing dudes don't want to be called out on, it's going to be their "manliness." Although this game doesn't need rules to be played, if you want to turn it into a competition, just go person-by-person and when someone refuses to do a dare -- or fails at it -- then eliminate him from the game. The person left standing gets to be crowned "top dude" for the night.
Poker
It doesn't get any more manly than poker. Make sure a deck of cards is around, grab some chips -- change can substitute if you're fresh out of chips -- and start playing. The most popular version of poker is Texas Hold 'Em, a game that has gained particular fame over the latter half of the 20th century when guys like Doyle Brunson and Chip Reese perfected it.
Versus Video Games
Playing video games -- especially competitive video games -- is another entertaining and exciting game for dudes. Real-time strategy games, first-person shooters and car-racing games are some of the choices that usually rev up the competition. If you want to make it really interesting, make everyone throw in some cash for a prize that goes to the winner.
Paintball War Games
If you want strategy, physical exercise and competition, then you want to play paintball. Physically and mentally challenging, dudes who play paintball team up and then take on the opposing team. If you have your own equipment, that's great, but if you don't, most large cities have paintball outlets where players can play and also rent equipment.