Cheap Flights to Madrid and Barcelona- from $356 Total Roundtrip
Spanair is a Madrid based Star Alliance carrier that does not fly to the US. However, they do file codeshares with their US based Star Alliance partners and from time to time their codeshared flights can be very cheap. It seems like they've loaded some extra cheap fares that may be of interest to many of you.
So far I've found total roundtrip prices from the following cities:
Boston: $356 on Orbitz
New Orleans: $396
Los Angeles: $502
San Diego: $551
Most flights are operated by US Airways, which actually has a pretty solid transatlantic Airbuss 330 product (with personal TVs at each seat in coach).
To find the cheap fares I used Orbitz.com and checked out the "Matrix" for cheap Spanair flights. You can also use travelocity.com -> flight search -> Enter in your city and then either Madrid or Barcelona-> Select flexible dates from now until October and then see if a cheap Spanair fare pops up. The calendar view only shows fall dates, but as Orbitz.com showed- this fare is more widely available. Feel free to comment below if you've been able to book a cheap ticket from your city.
Spain is a wonderful place to visit, so this could be a really fun mini-mileage run opportunity. The cheap fares seem to be available from non-Star Alliance hubs, so don't be surprised if its not available from your city. However, poke around and see if you can get it to load from a neighboring airport.
Feel free to check out this Flyertalk thread for more information. Hat tip to msp2msy for posting this great fare!