The race to the White House has spawned a flurry of mobile applications focusing on the presidential campaign -- from the deadly serious to the light-hearted and fun.

Businesses, non-profit organizations and political campaigns are capitalizing on the fact that nearly half of American adults own a smartphone -- and a growing number of these use them to keep up with or get involved in politics.

The Sunlight Foundation, for instance -- a non-profit group that seeks to use the Internet to achieve greater government openness and transparency -- has launched the mobile app Ad Hawk.

Hold up your smartphone to a television or radio when a political ad is aired, and you can find out who the sponsors are and who put up the money.

Another app called PollTracker -- created by Talking Points Memo, a web-based political journalism group -- provides polling data from the presidential race from a variety of sources, including Gallup.

Want to verify the truth of remarks made by Barack Obama or his Republican rival Mitt Romney? PolitiFact.com, a Tampa Bay Times project that fact-checks politicians, lobbyists and interest groups, has just the app for you.

Settle It! factchecks statements by keywords or names, and sets a politician's so-called Truth-O-Meter rating.

For voters who are still undecided -- a key focus of both candidates as the presidential race enters its final stages -- the "Who should I vote for?" app seeks to provide the answer.

It asks questions about issues such as health care, terrorism or education, and determines which candidate would be best suited to the user according to his or her answers.

News organizations have also launched their own apps. US Presidential 2012 goes a step further by delivering information about candidates from their own sites, blogs and social networks, as well as general campaign news.

A recent study by the Pew Research Center think tank found that 27 percent of registered voters who own a mobile phone had used it to get information about the White House race, and interact with campaigns and other voters.

VoterMap capitalizes on this trend, allowing users to write comments about the election anonymously, which are then geotagged onto a map. Other users can "like" or "dislike" the entry, and leave their own comments.

But it's not all serious, and some app developers have lightened the atmosphere with games and other quirky initiatives.

Election Game 2012, for example, puts you in the political hot seat, allowing you to manage your own election campaign by choosing where to spend money on political ads, travel or even when to make speeches.

One app developed by text-to-speech provider iSpeech allows users to type or speak a sentence and hear it played back in Obama's voice.

Even the candidates' campaign teams are in on the act. "With Mitt" allows users to take photos emblazoned with various slogans such as "I'm a Mom for Mitt" or "Obama isn't working."