Android Asset Studio lets you generate icons from existing source images, clipart, or text for inclusion into Android apps. This includes launcher, action bar, tab, notification and navigation drawer icons.
123D Circuits lets you design and simulate electronic circuits in a virtual breadboard environment. Arduino code is also supported. You can work on the design collaboratively like Google Docs. Currently the editor is designed for Google Chrome, so you might encounter problems with other browser. By default, the designs you create are public, and you will need to pay a monthly fee to make them private.
Cloudconvert lets you convert files between 140+ formats. Simply upload the file or poiint to the file in Drive or Dropbox, select the desired output format and start the conversion process. You can select to receive an email when the conversion is done, or get the converted file sent directly to Drive or Dropbox.