Walks and games of "chase" may also help to tire the puppy so they don't have as much energy and won't be as hyper. I agree with Des though. Although puppy's biting can be cute, everything you allow them to get away with at this age is setting them up for what they're will grow up to believe is acceptable when it's gets older.
It's important to set boundries and limitations now while they're still a puppy and "impressionable" rather than letting them get away with murder and than dealing with the after math when they're full grown and still not out of the "biting stage" ... As puppies teeth they will naturally want to chew things. I think setting the boundries that the puppy is only allowed to chew on their own toys is a good idea. Also, you can teach them to have a "soft mouth" meaning when they do "play bite" they don't bite down with so much pressure (This is more for when they're older), When the puppy is playing and is being bitey, say "OUCH" very loudly and and give them a "corrective touch" which is just a two finger touch. This is used to distract the brain and snap them out of the bad behavior. It's important to be consistant with this and soon the puppy will learn how much pressure before they hurt the human, and they will also learn that enough means enough.
Dogs see you as a "pack member". Other dogs in the pack will correct a dog's behavior if they see it be unacceptable. It's important as an owner that you now take on that responsibilty as becoming their "pack leader". Having a "calm assertive energy will you help to gain more respect as well as obedience, as dogs can sense our energy. The more frustrated you become, the more likely your dog will continue to exhibit the bad behaviour.
Remember though, Puppies are cute, but if you wouldn't let your child get away with being "bitey" why let your dog?! ... It might sound strange, but dogs need boundries and limitations just as much a small child does. They only get away with what you're willing to let them.
Make sure you're not giving affection to an excited state or to an action you don't want them doing. If you want the puppy to stop biting make sure you don't give affection until it does. Giving affection to an excited state that is exhibiting a bad behavior provokes confusion. When we give affection to a dog we're saying "this is the behaviour I want" ...
Goodluck!
Also, Pugs tend to be medium energy dogs. It's not so much that they don't have alot of energy, but they go through burts of energy however they can tire out very easily. Pugs for the most part are a pretty easy breed to train as they are eager to please and fairly low maintance.