I need ideas.

Halloween falls on a weekday again this year, and we are allowed - practically encouraged - to dress up at work.  Fun times.

I need ideas of cool/creative costumes I could put together with minimal effort/expense.  Last year I went as Puss in Boots and had a pretty good time of it.  All I had to buy was the mask and cape.

I wanted to do a seventeenth-century getup this year, but finding or making the skirts and shift and bodice was just too difficult and time-consuming, even if I cheated and used department-store plaid flannel for the arisaid.

So...suggestions?