In order to obtain todays dow jones index (DJIA) in a google spreadsheet one can use:
=GOOGLEFINANCE(".DJI")
The quotes matter. Indexes would be for example:
.DJI Dow jones Index
.INX S&P 500
.IXIC Nasdaq Composite
Getting the dow for a specific date is a bit more involved. This worked for me, but there might be an easier way:
=index(GOOGLEFINANCE(".DJI", "price", to_date(DATEVALUE("11/26/2013"))),2,2)
The date (11/26/2013) was actually a cell reference.
Not related, yet interesting was this page that showed how relative popular search terms are.
Others yielded interesting insights. For instance it seems that Cars are a seasonal product. Even though people tend to use them every day, they care more for them in the months leading up to summer.
Other extremely seasonal terms include: Travel, Shopping, Real Estate, Jobs and Durable Goods.