Roughly in this order, with the possible exception of item 3 and 4:
1) Double click the home button, hold down an app until they all jiggle, and then close the Puffin app by tapping on the minus sign. Try the app again.
2) Restart the iPad.
iPad: Turning on/off and resetting
3) Go to the Puffin site to see if there are announcements of server outages or trouble shooting guides.
Puffin for iOS - CloudMosa Hint: look at the bottom of the Puffin for iOS page for a trouble shooting tip.
4) Check the App Store reviews and see if some latest version isn't buggy, and you'll just have to wait for an update to fix it. (you'll want to be sure and do this last in order to squeeze maximum frustration from each app problem)
5) Delete the app by holding down on it until it starts to jiggle, and tapping the X. Then go to the App Store and download it again.
6) Be patient. Puffin, like all the Flash able browsers works through a server. It's possible that server is having problems, even if no one else has said anything about it yet.
7) Say the heck with it, go get iSwifter and forget all about Puffin. Maybe do this anyway, even if you get Puffin fixed.
Note: Just checked the App Store and Puffin's site/Facebook page. There have been no updates since 15 May, and no complaints about it crashing.