A recruiting manager sent me a very interesting little nugget this morning. The following was part of an actual offer letter that went out to a project manager in October of last year (it worked, they started early):
In consideration of the value of starting earlier than anticipated, you will earn a $2,000 signing bonus payable within your first two months of employment, if you are able to start on or before 10/22/07. This offer is not contingent upon that start date and is still valid for a start date as late as 11/5/07. This signing bonus is optional and only for consideration of an early start date.
I posted on the soon to be extinct custom of giving two weeks notice last year (ok, it was barely 3 weeks ago) but this is the first actual example I have been able to verify. The company that used this tactic was in a lot of pain and needed this person to start as soon as possible.