Thom Ferlisi didn't have time to answer his iPhone -- he was too busy. He had six museums to visit, and an iPad at stake.

Then he got a text, "which I stupidly replied to (wasting precious battery...!)" he recorded later on his blog.

Ferlisi's effort paid off -- he won a new iPad for coming in first place at last month's kickoff of goSmithsonian Trek, a smart-phone game that takes visitors through the nine Smithsonian museums along the National Mall, solving riddles, answering questions, writing haikus and taking pictures.

"I was excited about the game even before I knew that there was a prize to win," Ferlisi said. "They weren't expecting anyone to finish in the four-hour time frame. And then I show up, and there's still 50 minutes left on the clock."

This month's Smithsonian visitors also have the chance to win prizes by playing the game. The goSmithsonian Trek contest runs through July 24, when iPads will be awarded to the two top scorers.

Players earn points by completing challenges, most of which require answers to trivia questions about objects in the museums. "Two benevolent kings face off near the main entrance. What do they have to say?" asks one of the challenges for the Freer Gallery of Art.

Though the contest is only for visitors 18 years and older, the game was designed for players of all ages, said Beth Lieberman, who spearheaded the project for the visitors guide goSmithsonian.

"I talked to one mom who has a son who just can't stay away from the Smithsonian, and she was just bored with all the things he loves to come see. So she was really impressed with the game and it giving them another tool with which to see the museums," she said.

The trek is built on the game platform SCVNGR, which can be downloaded for free in the iPhone App Store or Android Market.

SCVNGR Chief Executive Officer Seth Priebatsch said hundreds of people have played the Smithsonian game since its release June 24.

"It's getting some awesome traffic," Priebatsch said.

The top score Tuesday was 284 points, by a player who had completed 69 out of 70 challenges.

Priebatsch founded SCVNGR two years ago while a freshman at Princeton University with the goal of "building a game layer on top of the real world," he said.

Players who get hooked on the Smithsonian's trek can check out other popular D.C. treks, including National Geographic, Gray Line, American University and the University of Maryland.