Although a very serious subject, I was quite amused by the letter left by Liam Byrne ex-Treasury secretary to the incoming David Laws (lettergate!)
This seems like quite a 'normal' thing to do when you have been displaced from your job, 'friendly' even. It apparently has precedent, James Callaghan getting a letter in 1964 from the outgoing Tories saying 'good luck old cock....sorry to leave it in such a mess'.
Other less friendly things to have done:
1. Block up all the staplers
2. Take the castors off the chairs
3. Take all the lightbulbs
4. Leave crumbs in all the keyboards
5. Hide the keys to all the cupboards
6. Put something nice behind the radiators - a dog turd perhaps?
I'm sure there are plenty of other ways to greet the new administration in a welcoming way.
By the way, I would love there to be some political issue concerning a scandal around a garden gate - just to see someone try to label this 'Gate-gate'.