Box, which provides cloud based storage, is offering 50 GB lifetime online storage to all Android users who sign up for the service between now and March 23, 2012. Existing users can get an upgrade to 50 GB by updating the app on their Android device. Normally, the Box offers 5 GB free storage. The maximum file size you can upload is 100 MB.
For business users Box offers 1000 GB of storage with a maximum file size of 2 GB. The paid version adds desktop sync and Goolge Apps integration among others.
The promo last a month. I suggest you head over to the Android Market and install the Box Android app to avail of the promo.