Mobile fitness app FitFu hopes to get you out of your desk chair and on the ground doing situps — through a combination of push notifications, short exercise routines, social features and motivational speeches from a strange blue creature.

FitFu, which will make its first appearance Tuesday as a member of Y Combinator's class of spring 2010, is trying to make "micro-exercise" a part of daily life. The startup's iPhone app sends periodical push notifications letting you know when it's time for a quick workout. The app also includes a Fu Time Diary so you can schedule your workouts in advance.

The $0.99 app reminds you to take a few minutes out of your day to do some crunches, squats, pushups or jack knives. The app utilizes the iPhone's accelerometer to track your progress, and provides motivational talk to keep you moving. If you do pullups with FitFu, your iPhone will call out how many you've completed and when you've reached your goal.

Some slick animations, designed by creative digital studio Despark, power these exercise routines. One of these animations is a blue creature with a snout that looks like a cross between an anteater and a toucan. The thing knows how to keep you motivated and engaged, which is one of the most difficult things about keeping a regular workout schedule.

Jof Arnold and Benjie Gillame founded FitFu and have been working together on iPhone apps since 2008. In addition to the money they received from Y Combinator, they have also raised funding from several angels and $150,000 in uncapped convertible debt from Yuri Milner and SV Angel's Start Fund.

To celebrate the newest version of its iPhone app and its debut at Y Combinator's Demo Day, the FitFu guys created a short video, below. If you try the app, let us know your experience in the comments.