Each play costs your pet 10 Energy and a Genie Lamp, but PetVille starts you off with 4 free Lamps. To get more Lamps, you can buy one for 2 Pet Cash each, or request them from friends via a Facebook Wall post. Friends who respond to your request will get a free Lamp too! Lamp requests are limited, however, as after the 4th or 5th request, your friend will stop getting free Lamps and start getting 100 Coins instead. Afterwards, it's no more Lamps 'til the next day.
It's been more than half a year since Zynga added its first mini-game to PetVille -- Bubble Pop. Personally, I was hoping that this gems game was more of a Bejeweled Blitz deal, like the one in Sorority Life or Treasure Madness, but Genie Gems is pretty fun and plays like a quick-and-dirty 9x9 version of Minesweeper.
In order to win, you need to run out of baskets without clicking on the Snake. Do that, and you'll also earn an "Extra Play", or free round.