Stack the log is one of those games which becomes blazingly addictive the more you play, involving stacking a bunch of logs on each other.

http://xwuz.com/stack/game.html

Knock Out is an iPhone version of the classic NES game Punch Out!

http://www.gyrocade.com/ko/

Educational quizzes to pass the time from your iPhone.

http://iquizshare.com/iphone/

Remote Desktop for Mobiles allows you to connect to your PC from anywhere, from your iPhone.

http://iphone.rdmplus.com

A simple mortgage calculator for your iPhone.

http://iphav.com/mc/Mortgage.html

Computes your monthly ovulation cycle.

http://ovulation.dynadel.com/

iPhone Yelp is an iPhone specific version of Yelp!. Yelp provides user submitted reviews for a variety of categories including restaurants, theaters, bars and much, much more. This version provides a Google Map view or a List view of the search results for a City or Neighborhood. To use, select a city and neighborhood, enter a search term, then press Map View or List View to see the results. Results are returned in the Highest User Rated order.

http://www.iphoneyelp.com

Magic iEight Ball responds to your questions by you simply rotating your iPhone.

http://www.ieightball.com/

Keep score on your golf game while on the course from your iPhone.

http://www.iphone18.com/

Need to tune up? Do it straight from your iPhone with this Guitar Tuning app.

http://iphoneguitartuner.com/