long story short, I was brand new in my office, they hadn't given me and office key yet, an I was the last one in the office option 1 was wait 4 hours for a coworker to return, or find a way to lock the door.
jump a few years into the future, and I just recently found myself in the same circumstance, last one in the office with my wife's car (and keys) so I had no office key. I was on my way in less than 5 minutes.
I'm sure if you think about it you can find a few more not so good uses, but you're on your own there!
Step 1: Materials
The tape can be just about any kind. Only a little strength is needed.
Clear packing tape seems to be a good choice.
Step 2: Setup
2. Cut a notch in one end.
3. Fold the tape over on to it's self.
Step 3: Double check
Step 4: Locking the door
stick the tape to the lever
fold it around the door.
close the door
pull the tape