I've been a Beeminder user for the past 3 years and I only recently learned that it's possible to keep track of pushups in a semi-automated way. Apparently this feature has been available since at least the end of 2013.
First, install the Beeminder app on your android smartphone and make sure you have created a "Do More" goal to track pushups (as of Dec 2015, you have to create new goals through the website). Then tap on your goal in the android app and select "Tally entry" mode by swiping to the right in the data entry box at bottom.
Finally tap once at the bottom around the zero and you will be taken to the following screen:
In tally entry mode, tapping the screen anywhere will record one data point. This is helpful when doing pushups, because when your nose or chin touches the smartphone screen, one pushup will be registered! When you are done, press your smartphone's back button and in the 2nd screen above, tap "Submit" to send you pushup data to Beeminder.
*Note: I find it easier to touch my chin to the smartphone screen as it allows me to look straight out instead of focusing on the floor as is the case when touching your nose to the screen.
http://blog.beeminder.com/beedroid/ (Manual Data Entry section)
http://blog.beeminder.com/faire/ (Pushups header)