As you know, Popfly is closing down on Aug 24th, the Popfly Team developed “Popfly Game Downloader,” to let you download and run Popfly games offline. Once installed, you’ll be able to run any shared Popfly game including your own and those built by the community. Mashups and private games are not supported, however.  To find community games to download, enter in a search term in the Game Downloader search box and then click “Go.” You’ll be taken to the game's homepage where you’ll notice a yellow toolbar which appears at the top of the screen prompting you to “click here” to download that game. Click the toolbar, and the Popfly Game Downloader will begin downloading the game for offline use. When it’s done, you’ll be given a link you can click to launch the game. Upon clicking, a new browser window will open revealing the html file that includes the offline version of the game.

More info: Download | Coding4Fun (detailed article)