bit of advice needed ...

[buffdaddy]

I would do it for 3 weeks since u have nothng lined up yet.

BUT make it very very very clear to them that this is not what u normally do and that you won't be extending for another 3 weeks at the end of this 3 weeks period.
also it could be the opportunity to negotiate a better rate

(for at least 3 weeks)

[Mustang]

Better off with just an extra 3 weeks than on the bench! Trust me!