This particular attack does not have to use jello but it is possibly most well known for the use of it with Jello in the television show the Office.  Basically in this attack you take all the items on a persons desk and wrap them in something like aluminum foil or suspend them in Jello.  This obviously works best if the person is out of the office for a day.  Further please don’t suspend electronic equipment in Jello, or if you do don’t blame me when it no longer works. 

If you do this to one of your co-workers send in a snapshot of it.